Jeff, a reader of this site, suggested this topic and I realized it was one that I should have written long ago.
You can make sense of all those numbers in the 24 hour kidney stone reports.
You can use those numbers to understand how things stand with you.
Reading the numbers can help you achieve your best possible chance at stone prevention – which is the only reason all those lab tests were done in the first place.
This article deals with calcium stones. A second one will cover uric acid stones.
Be Sure You Have Been Screened For Systemic Diseases
Your physician does this part. But even for systemic diseases stone risk is gauged in the urine so you can read along and assess how prevention is going.
Units of 24 hour Urine Measurements
Time
Because excretions of stone risk factors are in amount per 24 hours, we need the time of the collection. You provide the beginning and end times for the collection, in minutes and hours, and the laboratory corrects all excretion values to amounts in 24 hours.
For example, you start a urine collection at 7 am and complete it at 5 am the next morning. The measured total time is 22 hours. If the volume is 1.5 liters, the volume ‘corrected’ to 24 hours is 1.5 liters x 24 /22 (1.09) or 1.636 liters/24 hours.
It is obvious that the less ‘correcting’ the better, because the ‘correction’ assumes that every hour is the same as every other hour, which is not likely. So you want to collect as close to 24 hours as possible. If your time is below 22 or above 26 hours throw it away – no cost – and do another.
I am sure this is an unnecessary comment but sometimes people forget that a urine collection begins by emptying the bladder, writing down the time, and discarding the urine. Here and there people add it, making the real collection from whenever the bladder had last been emptied.
Volume per 24 Hours
Urine volume is measured in liters (L) or milliliters (ml). A milliliter is 1/1,000 of a liter, so there are 1,000 ml in a liter. One liter is 1.06 quarts. The laboratory measures the total volume of urine if you send or bring it. Often you will read the volume yourself, off of a collection container.
Because excretion rates like calcium, oxalate, citrate, and uric acid are calculated by multiplying their concentrations by the 24 hour volume, mistakes in timing, collection, or measurement of volume will make the results less valid. You provide the collection times, assure all the urine has been collected, and even may measure the volume, so quality is under your control.
Excretion Rates
Urine creatinine, calcium, oxalate, phosphate, and citrate excretions, are in milligrams (mg) or grams (gm) per 24 hours. A mg is 1/1,000 of a gram. An ounce contains 28.3 gm.
Urine sodium is measured in millimoles (mmol) or milliequivalents (mEq)/24 hours. Atoms, like sodium, each have a weight made up mainly of their constituent protons and neutrons. One mmol of sodium is 23 mg.
Some atoms like calcium have two charged sites which can bind to other molecules or atoms. They are often measured in milliequivalents (mEq) which is the weight times the number of sites. Sodium has only one, so mmol and mEq are the same.
Molecules like creatinine and oxalate have weights made up of their constituent atoms.
Conversion of Units
Some laboratories report in mmol or mEq. You can convert your lab report if it differs from mine. I will be using L for urine volume, mg for urine creatinine, calcium, oxalate, and citrate, and mmol for urine sodium. Here are the conversions:
Creatinine; 113 mg/mmol
Calcium: 40 mg/mmol; 20 mg/mEq
Sodium: 23 mg/mmol or mEq
Oxalate (oxalic acid): 88 mg/mmol; 44 mg/mEq
Citrate (citric acid): 189 mg/mmol
Direct Measurements
Acidity or alkalinity are measured in pH – no units. It is a logarithm to the base 10 so a change from 6 to 5 means a 10 fold increase in acidity, from 6 to 7 a ten fold increase in alkalinity.
Supersaturations are calculated from urine concentrations. The one we use here is the ratio of the concentration dissolved in urine of each of the three important stone forming salts, calcium oxalate, calcium phosphate, and uric acid divided by their individual solubilities at body temperature. Values below 1 mean crystals will dissolve. Values at one mean crystals will neither grow nor shrink nor form. Values above 1 mean crystals can form and grow. Being a ratio it has no units.
Is The 24 Hour Urine Valid?
Urine creatinine
Like all 24 hour excretion rates, that for creatinine is calculated from the concentration, measured volume, and collection time.
Because muscle cells make almost all the creatinine lost in urine any two urines you collect will have about the same amount of creatinine in them. A more than 20% variation between two urines suggests an error in one collection. If there are many collections, most creatinine excretions will line up pretty well, and an outlier – too high or low by more than 20% of the average for all the collections will stand out.
When a urine stands out as different from prior collections, I say it is best to repeat it. If there are two, use the one that seems more correct.
‘More correct’ is judged by expected amounts of urine creatinine. For men, one expects about 18 – 24 mg/kg body weight; for women, 16 – 22. A urine far out of those ranges is suspect. In people who have a high body fat percentage the ratio can be as low as 12 mg/kg/day, and people who have little body fat and a high muscle mass can be as high as 30 mg/kg/day.
Conditions of Collection
Did you eat and drink as usual, or show off? Had you ‘improved things’ since a recent stone so your collections reflect new habits and not those that led to the stones? Every collection is a one day frame out of a movie that is running 365 frames a year, so if these few days do not reliably represent your average life, their results will inevitably mislead you and your physicians and falsify what you came to do.
Reading the Results
Urine Volume
Curhan and colleagues have linked new onset of stones to urine volume in three large cohorts reviewed in our other articles. Take a look now. The graph is on page 2 of the article. Risk is on the vertical axis, and urine volume is on the horizontal axis. When red shows above the line at 1 it is above normal.
Risk is low above 2.25 liters/24 hours. But the day is long and the 24 hour urine is an average, so for insurance it is best to overshoot so the low times are still not too low. I would say 2.5 – 3 liters liters/24 hours is ideal.
Urine Calcium
Stone risk increases with urine calcium excretion above 200 mg/day in men and women – take a look. The calcium risk is at the upper left corner of the graph.
If you have above 200 mg/24 hours you have ‘hypercalciuria’, a high enough calcium to pose risk of stones – and also bone disease. There are many causes of hypercalciuria. The commonest is simply a genetic tendency, called idiopathic hypercalciuria. ‘Idiopathic’ means your physician has ruled out any of the other causes of hypercalciuria.
You lower urine calcium in idiopathic hypercalciuria with reduced diet sodium, avoidance of sugar loads, and medications if needed. You compare treated to untreated excretion to see how well the treatment worked.
Urine Sodium
Urine sodium is essentially the diet sodium intake. Because urine losses can lag intake when intake varies sharply, urine sodium is a good estimate of the average over 3 – 4 days. If you tried to lower your diet sodium to 100 mmol/24 hours, 2,300 mg intake, and you find 200 mmol/24 hours, you can be sure that your average intake is on average twice what you desired.
Suppose your urine calcium is 250 mg/24 hours, urine sodium 200 mmol/24 hours – twice the upper limit of diet sodium in the US and above the optimal value of 65 mmol (about 1,500 mg/24 hours). You would want to lower your diet sodium. Suppose your urine sodium was already 65 mmol/24 hours and urine calcium was 250 mg/24 hours; you would want to take other steps like thiazide diuretics or potassium citrate.
What if your urine calcium is 450 mg and your urine sodium is 200 mmol? Sounds like a bigger problem, but it is not. When urine calcium is higher the slope dependency of urine calcium on urine sodium is steeper, so the same reduction of sodium could bring urine calcium quite a way down.
If you lowered diet sodium and there is no change, do not assume the test is wrong. Check the creatinine values – do they match? If so, you have not lowered your average sodium intake. Sodium is an atom and you are not a cyclotron; you cannot make sodium or destroy it.
Sugar Loads
Given to people with idiopathic hypercalciuria they cause a rapid rise in urine calcium and supersaturation. The 24 hour urine will tend to underestimate this because of averaging throughout the day.
Thiazide Diuretics and Potassium Citrate
These drugs come after diet changes have not proven sufficient and are added to the diet changes.
Urine Oxalate
Stone risk increases with increasing urine oxalate and if the risk ratio is not as high as for calcium risk appears at very low levels of excretion – above 25 mg/day. In general, high urine oxalate comes from high oxalate diets, low calcium diets, or the combination of high oxalate and low calcium together. Therefore treatment is dietary. Excellent food lists are in this site – linked from the oxalate diet article. Rarely, urine oxalate is raised from a hereditary overproduction state – primary hyperoxaluria. Likewise, bowel diseases can raise urine oxalate. These are complex conditions and diet alone is rarely enough.
If urine oxalate is high and you have corrected both your diet oxalate intake and added significant diet calcium, you may have some form of genetic or acquired oxalate overproduction or an otherwise inapparent intestinal absorption problem.
Urine Citrate
Citrate is a powerful force against calcium stones. It binds calcium in a soluble complex. It interferes with calcium crystal formation and growth. Low urine citrate is a risk factor for new stone onset – bottom left panel of the graph. Above 400 mg daily there is no extra risk of stones in men or women, so ‘hypocitraturia’ means a urine citrate below 400 mg daily.
If you begin taking, as an example, four 10 mEq potassium citrate pills a day – 40 mEq, that extra 40 mEq of potassium should appear in the urine. If it is not there, the pills may not be delivering the medication into the blood from the bowel. The urine pH should rise because citrate imposes an alkali load. If it does not and the urine potassium does rise, you may need more of the medication.
Urine ammonia – I will cover this in the second half of this two part article – is a major way the body removes acid, so when you take citrate ammonia excretion should fall. If it does not fall, and urine potassium rises perhaps your pills are potassium chloride – the pharmacist switched from what was prescribed.
Strangely, the urine citrate itself does not rise in everyone even when potassium and pH rise and ammonia falls.
Urine pH
A low value – below 5.5 poses a risk of uric acid stones. A high value, above 6.2 raises calcium phosphate supersaturation and risk of calcium phosphate stones. Potassium citrate can raise urine pH; there are no medications to lower urine pH except methionine and ammonium chloride and these are not usable for stone prevention because they will increase urine calcium and pose a risk of bone mineral loss.
Urine Supersaturations
Get Them
If there are no supersaturations, ask that your samples be processed by a vendor that provides them. Supersaturation is the driving force for crystal formation and growth, and invaluable for monitoring stone prevention.
Relate Them To Your Stone Crystals
There will be three supersaturations: Calcium oxalate, calcium phosphate, and uric acid. Inspect the ones related to your stone crystals. For calcium oxalate both calcium oxalate and calcium phosphate supersaturations matter. If calcium phosphate, that one matters most. If pure uric acid, it is uric acid supersaturation.
Reduce Them
One should not compare values in a stone former to values in normal people, who often have urine supersaturations as high or higher than those of stone formers. Active stone formation means supersaturation is too high for you whatever the value may be and needs to be lower. You reduce your supersaturations by increasing urine volume and reducing excretions of calcium and oxalate, or raising excretion of citrate without undue increase of urine pH. That is why we make these measurements.
Compare Then to Now
Compare you now to you before your most recent fluid and diet intakes or medications: If they have fallen, things are going well; if they have risen things are not going well. If stones are still forming, supersaturations need to be lower. If there have been no more stones and supersaturations are stable, stand pat. If supersaturations are below 1 and stones are still forming, the urine samples do not properly represent your real life.
A Good Schedule
When? I like two 24 hour urines before treatment – it gives a sense of averages. After treatment has begun – diet changes, fluid goals, lifestyle, it is important to get another. The timing is up to patients: You know when something has changed, or ought to have changed, and need to be sure it has indeed changed in the right direction. It goes on like that until treatment is reaching its goals – lowering supersaturation by at least half – after which once a year is a good idea.
Thank you for your awesome site and resources. After suffering stones for a while, my Dr finally after bugging, sent me for a stone analysis and 24 urine collection. Here are my results.
Stone type: Calcium Oxalate Dihydrate / Calcium Phosphate mixed
I did 3 days of urine testing (way it’s done in my Province, 1 jug is no additive, 1 has HCL, 1 has NAOH) My volumes for the 3 days were 2.3L, 3.6L, 2.6L
Creatinine 7.1 mmol/L
Urate 1.5 mmol/L
Creatinine 5.8 mmol/L (day 2 jug)
Oxalate 115 umol/L
Creatinine 4.4 mmol/L (day 3 jug)
Magnesium 1.5 mmol/L
Calcium 1.76 mmol/L
I still have to go for blood work, but at least after a year of suffering, I have the ball rolling. I currently have 13 stones between both kidneys, ranging from 3mm to 13mm. I’m making them frequently, so I’m hoping these urine results can shed some light on what’s going on.
Phosphate 6.95 mmol/L (THIS IS MARKED AS LOW VALUE)
Citrate 1.25 mmol/L
Hi Jay, I would like to help but the data seem fragmented. Perhaps you could post one urine with its volume, calcium, creatinine, citrate and pH so I could look at an ensemble. If you have 2 with complete data so much the better. Isolated values are very hard to interpret. Likewise, pH and calcium and need to be in the same place as you have enough phosphate in your stones to worry about that pH dependent phase. Regards, Fred
Is a oxalate score of 44 considered high?
Hi Linda, Urine oxalate of 44 mg/24 hours is high enough to pose an increased risk for calcium oxalate stones. The cause is likely dietary.Take a look at the linked article for how to think about lowering it. Regards, Fred Coe
Hi, Dr. Coe! I am a 24 year old female, who passed their first stone in October 2023. I went to the ER, since I had no idea what this type of pain could have meant, and was told that I had two kidney stones, one on each side. Thankfully, I passed one 5mm kidney stone, but I still have a 6mm on my left kidney. I went to the Urologist, and he performed a 24hr-Urine collection. I was wondering, if you’d be able to shed some light on my results and offer any recommendations! So far, I was told to lower red meats and take potassium citrate twice daily. I also tend to take protein shakes (24g) and creatine (5g), three times a week, whenever I go to the gym. Is this something that I should consider stopping? I really appreciate any feedback, thank you so much! Just trying to figure out how to find a new balanced diet to prevent any future kidney stone formations.
Height: 5′ 2″
Weight: 125
Here are my results:
Calcium Oxalate Saturation: 3.31 (Low)
Calcium, Urine: 258 (High)
Oxalate, Urine: 19 (Low)
Citrate, Urine: 328 (Low)
Calcium Phosphate Saturation: 1.37 (In Range)
pH, 24 hr, Urine: 6.345 (High)
Uric Acid Saturation: 0.34 (In Range)
Uric Acid, Urine: 754 (High)
Sodium, Urine: 116 (In Range)
Potassium, Urine; 50 (In Range)
Magnesium, Urine: 93 (In Range)
Phosphorus, Urine: 854 (In Range)
Ammonium, Urine: 61 (High)
Chloride, Urine: 125 (In Range)
Sulfate, Urine: 59 (In Range)
Urea Nitrogen, Urine: 13.52 (In Range)
Protein Catabolic Rate: 1.6 (High)
Creatinine, Urine: 1125 (In Range)
Creatinine/Kg Body Weight: 19.1 (High)
Calcium/Kg Body Weight: 4.4 (High)
Calcium/Creatinine Ratio: 229 (In Range)
Thank you!
Hi Jocelyn, Your PCR (protein intake) is 1.6 gm/kg/day a colossal value that will raise urine calcium and risk of stones. Your urine calcium is very high and your urine pH high enough for you to make calcium phosphate stones. I would stop the protein shakes and creatinine, and the potassium citrate, wait two weeks, and get another 24 hour urine. I predict a lot lower urine calcium and less stone risk. Perhaps you have idiopathic hypercalciuria, in which case one can make reasonable treatment offerings based on diet. But with the protein loading nothing can be determined properly. Regards, Fred Coe
Hello Doctor, I had a large 1.5cm calcium oxalate stone in Aug. 0f 23. It was remove by Shock Wave Lithotripsy. My resent 24 hour urine test from March of 2024:..
Specimen vol. 3.24
PH Urine 5.6
Calcium Rate 208
Oxalate Rate 27
Uric Acid Rate 914
Citrate 342
Sodium 137
Sulfate 14
Phosphate 1050
Magnesium 107
Ammonia 33
Potassium 60
Creatinine 1594
Calcium Oxalate .76
Brushite Rel. Supersaturation .33
Sodium urate Relative superstar. .70
Struvite Rel. Super Satu. .03
Uric Acid Rel. Super Satu. 2.34
Hi Howard, Your results show an acid urine with no SS for calcium oxalate or calcium phosphate but considerable SS for uric acid. I wonder if the stone was indeed CaOx. If it was then this urine reflects different conditions of diet and lifestyle from when it formed. Of incidental interest, urine ammonia is far higher than urine sulfate. This often arises from bowel disease, laxative excess, or underlying systemic diseases. I do not have enough information to say more about it. Regards, Fred Coe
Dear Dr. Coe thank you so much for taking the time to read our results. I had my first kidney stone at age 54. I see the urologist every six months, and this is my second urine test. The first one was “perfect” according to the doctor. The second appears different. I increase my calcium since watching Jill’s diet recommendation, like calcium at every meal. I eat meat once or twice a week. I would be grateful if you could help me interpret the following. It seems that I need to reduce the calcium
Urine Volume 4220 (3600 a year ago, I exercise and live in Texas) HIGH
Calcium Oxalate Saturation 2.38 (2.07 a year ago) LOW
Calcium, Urine 231 (152 a year ago) HIGH
oxalate, Urine 27
Citrate, Urine 748
Calcium Phosphate Saturation 0. 86
PpH, 24 hr, Urine 6.874 (6.711 a year ago) HIGH
Uric Acid Saturation 0.05
Uric Acid, Urine 552
Sodium, Urine 58
Potassium, Urine 58
Magnesium, Urine 161(92 a year ago) HIGH
Phosphorus, Urine 584 (366 a year ago) LOW
Ammonium, Urine 24
Chloride, Urine <63 (<54 a year ago) HIGH
Sulfate, Urine 27
Urea Nitrogen, Urine 6.64
Protein Catabolic Rate 1.0
Creatinine, Urine 954
Creatinine/Kg Body Weight 19.5
Calcium/Kg Body Weight 4.7 (3.1 a year ago) HIGH
Calcium/Creatinine Ratio 242
With gratitude Dr. Coe
Hi San, You did well to increase diet calcium – bones, which revealed an underlying idiopathic hypercalciuria. The low sodium high calcium diet is good. Even if your very high urine volume was not sustainable you should be reasonably safe. Best, Fred Coe
I am a 75 year old woman with state IIIb CKD caused by injury to the kidneys from septic shock. I had a Roux-N-Y bypass more than 30 years ago. I take sodium bicarb for metabolic acidosis. I recently had an obstructing stone, diagnosed with a CT of my kidney and removed surgically. As far as I know, it’s my first stone. Results of my 24 stone urinalysis:
Urine volume: 1.8 L
pH: 5.2
Calcium: 21.6 mg
Sodium: 140.4 mEq
Citrate: <50 mg/ml
Magnesium: 76.6 mg
Oxylate: 128.3 mg
Uric Acid: 165.6 mg
Phosphorus: 846 mg
Sulfate: 5 mmol
Chloride: 104.4 mEq
Creatinine: 702 mg
Calcium Oxylate RSR 0.6
I've continued my low fat diet to decrease gastric issues, increased my fluid intake, am taking potassium citrate, as prescribed, and limiting very high oxylate foods like spinach, beets and rhubarb. Anything else I should consider?
Hi Casie, Because of the Roux-N-Y procedure your urine oxalate is very high. Because of your CKD urine calcium is low as is citrate and pH. With falling filtration rate the high urine oxalate poses a subtle risk for worsening kidney disease and even systemic disease. CaOx crystals can form high up in the kidney cortex and worsen kidney function. Serum oxalate can rise and crystals form within the body. I would urge your physicians give some thought to the risks from the bypass in your situation. From this distance there is little else I can add. Potassium citrate will not protect your in this situation, and food oxalate limitations have clearly not been of much help. Regards, Fred Coe
Hi Dr Coe
I’m 41 never had issues before with stones but I took myself off of Valium I was on it for 10 years and my whole system has gone nuts. I have 11 small stones in total 1-3mm in both kidneys here is my 24 hour urine.
Urine Volume (Preserved) 5240
Calcium Oxalate Saturation 1.90
A Calcium, Urine°255
Oxalate, Urine 30
Citrate, Urine 533
Calcium Phosphate
Saturation 0.64
A pH, 24 hr, Urine 6.687
Uric Acid Saturation 0.07
Uric Acid, Urine 765
Sodium, Urine 177
Potassium, Urine 85
Magnesium, Urine 90
Phosphorus, Urine 907
Ammonium, Urine 65
Chloride, Urine 202
Sulfate, Urine 50
Urea Nitrogen, Urine 12.07
Protein Catabolic Rate 11
Creatinine, Urine 1263
Creatinine/Kg Body Weight 14.9
Calcium/Kg Body Weight 3.0
Calcium/Creatinine Ratio 199
I’m not sure how to fix this or if I can
Hi Katie, Your urine calcium is high. With your present high urine volume new stones are impossible but this is obviously a new happening. I suspect urine volume was lower in the past. Perhaps diet change might be a good first step if your physicians agree. Regards, Fred Coe
Thank you so much you are amazing. I am trying to lower my sodium in hopes my calcium continues to come down it was 285 then 255 I’m hoping with sodium lowered it’ll keep going down. I did read that high cortisol can also pull calcium into the urine I’m wondering if that’s the issue because I’m in medication withdrawal and it’s taxed my body and adrenals to the max. I’m hoping this continues to get better ❤️🩹
Hi Katie, Secondary high cortisol does not usually raise urine calcium. The sodium approach is ideal, if it works for your way of eating. Best, Fred Coe
Hi Fred! I recently had a stone removed again and my urologist asked me to get a 24 hour urine test. Could you provide thoughts on these test results? The stone was 90% carbonate apatite and 10% calcium oxalate.
Volume – 1.43 L
Cystine – Negative
CaOx Sat – 3.18
Calcium – 48 mg
Oxalate – 32mg
Citrate – <22mg
CaPO4 sat – 0.76
pH – 6.46
Uric Acid Sat – 0.39
Uric Acid – 700mg
Sodium – 80 mmol
Potassium – 37 mmol
Magnesium – 38 mmol
Phosphorus – 937 mg
Ammonium – 37 mmol
Chloride – 66 mmol
Sulfate – 22 mEq
Urea Nitrogen – 7.54 g
Protein Catabolic Rate – 1.0
Creatinine – 1,441 mg
Creatinine/kg – 23.5 mg/kg
Calcium/kg – 0.8 mg/kg
Calcium/creatinine – 33 mg/g
Hi Jill, how odd a situation! A calcium phosphate stone, and a 24 hour urine actually below normal in calcium. At first I believed you posted urine concentrations, not amounts/24 hours so I mentally multiplied by 1.43 l/d. But as the urine concentration for calcium is measured in mg/100 mg yours 1.73 l/d times 480 mg/l, way too high. So I came to think these are per day, urine calcium is very low, oxalate borderline high, and all SS values low yet you formed calcium phosphate crystals and a stone. How did this happen? The urine is very alkaline, pH 6.46, citrate is too low to measure, so we lose a main inhibitor of crystal formation. All we need is (are) episode(s) of low urine flow to concentrate the calcium salts so that the high pH and low citrate will support calcium phosphate crystals and you will have the answer. But why the low citrate? Is is genes? Are you taking a medication that might lower urine citrate and raise urine pH? Do you have a form of renal tubular acidosis? With so little information, I can go no further. Best, Fred
Dr. Coe,
I recently had my first kidney stone (around 7mm), which I passed about 2 weeks after diagnosis. My brother and multiple family members also have a history of kidney stones. The urologist sent my stone for analysis, had me complete a 24 hour urine and referred me to renal clinic (I also have a history of vesicoureteral reflux as a child on the side where the stone was located). CT at the time I presented with kidney stone to the ER showed moderately severe hydronephrosis and the urology fellow on call mentioned that my renal parenchyma was low on that side but he didn’t seem super concerned about it (my mother has since told me that my left kidney was noted to be smaller than the right when I was worked up as a child). The results of stone analysis and 24 hour urine are below. I realize that I need to drink more water which I will start to focus on but wondering any other recs based on this profile. I won’t be seen in the renal clinic until early Sept. but would like to start making any recommended modifications. I also have a diagnosis of ulcerative colitis. I am in my mid 40s, around 5’1″ and around 105 pounds.
COMPONENT 1 (CALCULUS): Calcium Oxalate Dihydrate (Weddellite) 30%
Calcium Oxalate Monohydrate (Whewellite) 35%
Carbonate Apatite (Dahllite) 35%
24 hr Urine:
PH, URINE 6.8 QUEST REF LAB
CALCIUM, URINE 195 mg/day
SODIUM URINE 141 mEq/day
POTASSIUM, URINE 33 mEq/day
PHOSPHORUS, URINE 689 mg/day
MAGNESIUM, URINE 51 Low mg/day
SULFATE URINE 10 mmol/day
BRUSHITE 3.55 High
SODIUM URATE 2.25 High
URIC ACID CALC 0.21
TOTAL VOLUME,URORISK 1.43 Low L/day
URORISK OXALATE 19 mg/day
URORISK CREATININE 921 mg/day
CALCIUM OXALATE 1.36
URORISK URIC ACID 386 mg/day
URINE CITRATE 630 mg/day
SUPERSATURATION IN W/RESPECT TO:
BRUSHITE
SODIUM URATE
URIC ACID
Low urine volume
Brushite (Ca phosphate)
Monosodium urate
Dear Cynthia, Your urine is very alkaline – pH 6.8 and you seem to have a high supersaturation with respect to brushite – your stone is 35% calcium phosphate. The low volume is an obvious problem that you can fix out of hand. Your urine calcium is hefty, just below overt increase in stone risk, and in part this is due to your high diet sodium (140 mEq in the urine is the diet intake) so you might want to moderate that to 1500 mg (65 mEq) daily. The stone formed in an injured kidney (smaller) and the urine from that kidney may be even more alkaline, moreover the drainage from that side may be abnormal fostering stones. That is about all I can do to help you without actually knowing your medical condition. Regards, Fred Coe
These are the results from my 24 hour urine collection.
Urine Volume 2.35
SS CaOx 6.79
Urine Calcium 303
Urine Oxalate 31
Urine Citrate 540
SS CaP 0.41
24 Hour Urine ph 5.608
SS Uric Acid 0.85
Urine Uric Acid 0.503
My stones are Calcium Oxalate
Monohydrate 15%
Dihydrate 80%
Hydroxyapatite 5%
I am currently drinking 3 liters of water per day, eating close to 1200 mg of Calcium rich foods, getting up to 1500 mg of sodium and eating under 25 mg of added sugar daily. Is there anything else I should be doing?
Hi Brenda, You are pretty typical of a woman calcium oxalate stone former. Your urine calcium is high enough to pose risk of more stones, and you did not post your urine sodium – is it really 65 mE1 (1500 mg)? If not, get it to be. If that fails, thiazide would be the next step. Regards, Fred Coe
Good Day Dr Coe,
My recent Litholink is very good except for 2 metrics. (My previous Litholink was in Dec 2020):
Mg24 was 182 dropped to 51. Since 2016 the range has been 116 – 182 so this is puzzling.
pH was 5.813 now is high at 6.877
I currently take Pot Citrate 15MEQ 2 tabs twice daily and have been on this dosage for the past year. My pH has done this before. In 2019 under the care of a different doc it went up to 6.782 who over-reduced Pot. Citrate. Since we switched doctors I am confident our current doctor can tweak the Pot Citrate dosage, so am not too concerned about this.
Regarding the drop in Mg24 – I have been taking a Mg supplement as Mg Threonate 3tbs/day each 144mg for the past 4 years – consistent with the prior Litholink. I am also on a thiazide – Indapamide – on a dosage that has been constant for the past 4 years. In fact I have had no Rx changes for the past 1 and 1/2 years.
I would appreciate any thoughts you might have.
In case other metrics might suggest a reason here they are:
Vol 24 – 3.99
SS CaOx – 0.81
Ca 24 – 73
Ox 24 – 28
Cit 24 – 585
SS CaP – 0.34
pH 24 – 6.877
SS UA – 0.04
UA 24 – 0.541
Na 24 – 223
K 24 – 96
Mg 24 – 51
P 24 – 1.006
Nh4 24 – 14
Cl 24 – 205
Sul 24 – 43
UUN 24 – 11.94
PCR – 0.9
Regards
Brent
Hi Brent, thiazide causes magnesium wasting, and you are probably depleted – most magnesium is in cells not blood. Your supplement is too modest – try 400 mf OTC Mg oxide, 1 or 2 a day. Your diet sodium (223 mEq/d) is way too high, a reasonable upper limit is 100 mEq (2300 mg). The high sodium load worsens potassium and magnesium loss. Urine pH rises inevitably with alkali – nothing can be done about it. Your stone risk is low. Regards, Fred Coe
Hi Dr. Coe!
I am currently going through the process to donate one of my kidneys. On my initial visit, a microscopic urinalysis showed a moderate value for Calcium Oxalate Crystals. It was recommended that I complete a 24-hour stone analysis. I am a 41 year old female and do not have a history of stones. It was thought I may have had one 6 years ago, but if I did I was able to pass without knowing it. Below are the results of the 24-hour stone analysis:
Urine Volume: 1.84L
SS CaOx: 6.99
Urine Calcium: 175mg
Urine Oxalate: 31mg
Urine Citrate: 1037mg
SS CaP: 1.13
24 Hour Urine PH: 6.478
SS Uric Acid: 0.16
Urine Uric Acid: 0.377g
The transplant team recommended I go over the results with my PC. My PC suggested that I discontinue the prenatal vitamins and other supplements, and be mindful of foods that are high in calcium and vitamin C. I made the changes (also increased my average water consumption to 2.5-3L perday) and repeated the 24-hour stone analysis 90-days after the initial test. Below are those results:
Urine Volume: 1.82L
SS CaOx: 8.01
Urine Calcium: 381mg
Urine Oxalate: 26mg
Urine Citrate: 1306mg
SS CaP: 1.29
24 Hour Urine PH: 5.864
SS Uric Acid: 0.76
Urine Uric Acid: 0.527g
Needless to say, my numbers did not go in the direction I was anticipating. The transplant team has now recommended that I meet with their kidney stone clinic, but am unable to get in until the end of October. Are you able to provide any recommendations?
Any tips are greatly appreciated!
Thanks!
Lea
Hi Lea, assuming your blood calcium is normal you have idiopathic – genetic – hypercalciuria. Urine calcium is very responsive to diet sodium, and I imagine that went up between the two collections. If I were asked, I would not encourage donation as your urine calcium is quite high, you made obvious crystals and will have only one kidney. Low calcium diet with IH is not good for bones, and bone disease is well described. Likewise, I noticed a very high urine citrate despite a rather low urine pH in the second collection – perhaps your nephrologists might want to ponder that in terms of other health risk factors such as blood lipids, blood pressure, and blood glucose to be sure there are not problems there – I am an outsider, so this is mere suggestions to the wise. Regards, Fred Coe
Hi Dr. Coe,
Thank you for your time. Here’s my 48Hr Litholink report. I had CaOx stones, 49yr, 133lb, exercise 5 days a week. The Day2 collection volume was lower, likely due to it being a day I exercised. The Na 24 was higher on Day2 due to electrolyte consumption I am guessing.
Since both ph and citrate are low, am I a good candidate for Potassium Citrate supplementation? I have since increased my water intake.
Collection Day 1:
Urine Volume – 2.68
SS CaOx (liters/day) – 5.90
Urine Calcium (mg/day) – 372
Urine Oxalate (mg/day) – 35
Urine Citrate (mg/day) – 291
24 Hour Urine pH – 5.288
SS CaP – 0.25
SS Uric Acid – 1.22
Urine Uric Acid (g/day) – 0.544
Collection Day 2:
Urine Volume – 2.15
SS CaOx (liters/day) – 7.01
Urine Calcium (mg/day) – 350
Urine Oxalate (mg/day) – 34
Urine Citrate (mg/day) – 360
24 Hour Urine pH – 5.426
SS CaP – 0.24
SS Uric Acid – 1.24
Urine Uric Acid (g/day) – 0.525
Dietary Factors – Day1, Day2 values (comma separated)
Na 24 – 94, 144
K 24 – 35, 45
Mg 24 – 196, 168
P 24 – 0.971, 0.756
Nh4 24 – 54, 42
Cl 24 – 107, 161
Sul 24 – 53, 47
UUN 24 – 11.93, 9.91
PCR – 1.5, 1.2
Hi snair, Your urine calcium is very high, and a prime issue for your stones. I would not use potassium citrate for fear of converting to calcium phosphate stones, but would suggest higher urine volume – to 3 liters/d as possible – and probably a thiazide diuretic to lower your urine calcium – depending on how much of a problem the stones pose. I presume your serum calcium is normal, and if so you have idiopathic hypercalciuria. If it is even a slight bit high, you could have primary hyperparathyroidism – but I doubt it. Regards, Fred Coe
I’ve had multiple stones mostly when I’ve been pregnant. I have 3 children. I do take potassium cit, citrate 10ml 2 times a day but honestly I always forget at night.
Stone risk factor
Vol: 1.27
SS CaOx: 8.24
Ca 24: 222
Ox 24: 31
Cit 24: 528
SS CaP: 4.66
Ph: 7.1
SS UA: 0.10
Ua 24: 0.779
Dietary factors
Na 24: 161
K 24: 71
Mg 24: 88
P24: 0.896
Nh4 24: 19
Cl 24: 121
Sul 24: 45
UUN 24: 11.90
PCR: 1.4
Normalized values
Cr 24: 1361
Cr 24 kg: 22.7
Ca 24 kg: 3.7
Ca 24/ cr 24 163
Hi Melinda, The fact that most catches my eye is the remarkably low urine volume. So low that stone prevention is impossible. How about more than double? Three liters a day would perhaps be all you need for prevention. The potassium citrate is raising your urine pH and risk for CaP stones, and even with it your citrate is not all that high – 525. Not sure if it is good or not for prevention – something your physician has to figure out. Regards, Fred Coe
My urine sodium was 125 and My report said Treat with diet sodium 2300-3500 mg/day
Hi Brenda, The tolerable upper limit for diet sodium – urine sodium is diet sodium on average – is 100 mEq which is 2300 mg/d. Thence the note. Fred
So if I’m understanding you correctly I should be consuming no more than 2300 mg/ sodium daily?
Hi Brenda, 2300 mg of sodium is the ‘tolerable upper limit’ of sodium for the US population, so yes. Fred
Hi Dr. Coe. I’ve had 9 stones in my life (from 18 to 55 years old). 4 have been tested, and all were Calcium Oxalate Dihydrate (Weddellite) 15%, Calcium Oxalate Monohydrate (Whewellite) 70%, Carbonate Apatite (Dahllite) 15%.
3 years ago I increased my water intake to 4 liters / day, mixed with 1/2 cup of lemon juice concentrate, but continued a diet medium-high in sodium, low calcium, and high oxalate. In May, I ended up with 2 more 9mm stones (one of which was analyzed as listed above). I then found your site (thank you!) and significantly reduced my sodium intake to ~800-1,000mg / day, calcium ~= 1,000, and ceased eating the super high oxalate (I used to eat a LOT of spinach). I’ve been on this new diet for 3 months now.
My first ever 24/hour urine test just came back from Litholink, and I seem to be a bit unlucky. My urine sodium is wonderfully low, my oxalate is almost ok, but my urine calcium is still relatively high, especially considering how low my sodium is. Considering I don’t get a TON of stones, are my current results good enough, or do I need to do more? For instance, my oxalate intake is ~175mg / day.
Urine Volume: 3.65
SS CaOx: 3.73
Urine Calcium: 290
Urine Oxalate: 31
Urine Citrate: 579
SS CaP: 1.74
24 hour Urine pH: 6.962
SS Uric Acid: 0.04
Urine Uric Acid: 0.456
Na 24: <36
K 24: 103
Mg 24: 129
P 24: 0.847
Nh4 24: 23
Ci 24: <55
Sul 24: 39
UUN 24: 9.01
PCR: 1.1
Normalized Values:
Cr 24: 1420
Cr 24/Kg: 22.8
Ca 24/Kg: 4.7
Ca 24/Cr 24: 204
I also had a CBC and Metabolic blood work done, though 1 day later.
Blood sodium: 139
Potassium: 3.9
Creatinine: 0.95
Bun/Creatinine: 14.7
These values are consistent with the past 5+ years of annual blood work.
Thoughts? TIA!!!!
I should have included my Serum Calcium: 9.0.
Hi Cameron, I believe I already discussed these values for you with a first name Brett – I recognized the urine sodium and calcium. Fred
Hi Dr. Coe,
Thank you for your website, it has changed my life! I am 5’7”, 135lb, semi-athletic, 55-year old male, who has had nine confirmed kidney stones in my life, the first at the age of 19. Four stones have required surgeries, one via SWL and three (including two in May) via lithotripsy. My stone in 2018 and one of the two in May were analyzed as Calcium Oxalate Dihydrate (Weddellite) 15%, Calcium Oxalate Monohydrate (Whewellite) 70%, Carbonate Apatite (Dahllite) 15%, and two previous stones 10+ years ago were also Calcium Oxalate.
In 2018, I increased my water intake to 4-liters/day mixed with 1/2 cup of lemon juice, but was probably ingesting ~3,000mg sodium, < 500mg of calcium/day, and eating a lot of spinach, etc. Not surprisingly, I still ended up with two large stones 3 years later. In May, I discovered your site and have been following a 700-1,000mg sodium, 950-1,100mg calcium and 125-200mg oxalate per day diet since May. As a result of this new diet my chronic hypertension is almost completely gone (reducing Enalapril from 40mg to 2.5mg / day).
I completed my first ever 24-hour analysis last week, with blood work done the next day. My results are below. In consultation with my GP and urologist, I am switching my HBP medication from Enalapril to two 12.5mg Hydrochlorothiazide/day, in the hopes that the HCL will both control my hypertension and lower my urine calcium. I will do a 2nd 24-hour collection in January.
My questions for you are: Should I be concerned re: my urine pH and SS CaP? Do I need to reduce my oxalate intake? Do you believe I have reduced my sodium too much, since my urine sodium is so low? Am I semi-unique in that my urine sodium is <36 but my urine calcium is still 290? I definitely am an outlier on your urine calcium vs urine sodium chart! 🙁
Thank you again for providing such valuable data and insight to all of us!
Urine Volume: 3.65
SS CaOx: 3.73
Urine Calcium: 290
Urine Oxalate: 31
Urine Citrate: 579
SS CaP: 1.74
24 hour Urine pH: 6.962
SS Uric Acid: 0.04
Urine Uric Acid: 0.456
Na 24: <36
K 24: 103
Mg 24: 129
P 24: 0.847
Nh4 24: 23
Ci 24: <55
Sul 24: 39
UUN 24: 9.01
PCR: 1.1
Normalized Values:
Cr 24: 1420
Cr 24/Kg: 22.8
Ca 24/Kg: 4.7
Ca 24/Cr 24: 204
Metabolic blood test results:
Sodium: 139
Potassium: 3.9
Calcium: 9.0
Creatinine: 0.95
Bun/Creatinine: 14.7
Hi Brett, What a great outcome! Lowering diet sodium really does lower BP and the switch to a thiazide is smart in that it will lower urine calcium and replace the pril. With such a low diet sodium and high a water intake, adding thiazide might lower serum sodium, so your physician better check at one week and one month to be sure. I might start with a lower dose of the thiazide, perhaps 12.5 daily – and follow home BP – more predictive than office measurements. I do not think you have lowered diet sodium too much – over 3 liters of urine, lower limit of sodium is partly low intake and partly dilution so we do not really know your total daily sodium loss. But if it were 40 mEq/day, in 3.65 liters of urine, its concentration would be too low to measure Regards, Fred Coe
Ty Dr. Coe! Yes, sorry for the duplicate entry, I wasn’t sure if my original went through. To keep my BP under control, it’s looking like I will be on 25mg of Hydrochlorothiazide, twice a day (my BP was too high on 12.5mg x2). As for follow-up blood work, that is definitely happening. I am excited that I’ll be down to one medication that will hopefully take care of both my hypertension and hypercalciuria.
Is there anything else I should be doing, for instance, should I be concerned re: my urine pH and SS CaP, or since I don’t have a history of Calcium-Phosphate stones, I should be ok in that regard? Thank you again!
Hi Brett, You want SS CaP below 1, but the pill may achieve that. Chlorthalidone 12.5 mg/d does lower urine pH – we published that – so if the OHCTZ does not achieve a low SS CaP perhaps the CTD will. Low diet sodium is important so use 24 hour urine testing to know what it is. Fred
Hi Dr. Coe. I’m having some difficulties with some HCTZ side-effects, the worse being that my tinnitus seems to be worse. I’ve moved up my next 24-urine test to be middle of September (ie, 6 weeks after starting the HCTZ), to see if the HCTZ lowered my urine calcium, so I’ll stay on the HCTZ till after the results are in. My question for you is, with my urine calcium at 290, sodium < 36, and oxalate at 31, how likely is it for me to get more CO stones, if I end up not taking a thiazide (all thiazides seem to exacerbate tinnitus)? Maybe my tinnitus will subside with time, but hasn't so far. 🙁 Sorry for all the questions.
Hi Brett, The best risk assay is the SS for CaOx and CaP; if you can get the former under 3 and the latter under 1 you are pretty safe. Without thiazide, your best BP drug is a sartan – I like Losartan. Be sure and follow home BP as these are most predictive of outcomes. Fred
Funny you mention a sartan! My GP and I have found the correct BP balance for me with the Losartan 50mg / 12.5 HCTZ pill. Hopefully it will help my urine calcium level.
Currently & for the past 3 years, I drink 1/2 cup of lemon juice concentrate mixed with a ~gallon of water / day. I assume the lemon juice is improving my citrate, but is it also contributing to my urine Ph? Should I cut back on it a bit, or leave it well enough alone? Thanks as always!
Hi Brett, As I do not really know the details of your medical situation, I should refrain from too much intervention that might be a disservice. For example the exact balance between citrate and pH response to a citrate load require one see the whole picture – that is your physician. Fred
I understand. My last last question, if you are willing… How is it possible that my urinary sodium is so low (<36) while my urine calcium is still so high (290)? I am concerned that my Intermittent Fasting, in which I ingest ~500mg of calcium twice/day, but only separated by ~4.5 hours is causing (at least in part) my high urinary calcium. Do you believe that is possible? Would it be better to be ingesting ~350mg of calcium via three meals, each separated by ~4 hours?
I've read NIH articles, etc, and I can't find any clear statement, other than non-cited declarations that ingesting too much calcium at one meal causes elevated urinary calcium levels, which I am not sure is true or not! 🙁
Hi Brett, I have presumed you take your calcium as food. Supplements without food is not a good idea. If you must use supplements take them with your larger meals to assure a slower absorption. The problem I alluded to in a prior note is haunting us here. I do not know the details of your stone disease or your life in general, so as I am pushed to provide more detailed advice errors can easily occur. If you want me to provide detailed advice, I do telemedicine and can provide exactly what one would want, at the expense of considerable time and effort for us both. In a public forum, where I am rather ignorant of details, I fear misleading you. Regards, Fred
Hi Brett, There is no basis for estimating. Thiazide lowered stones by about 50% vs. nothing in trials but there are no trials of thiazide vs. low sodium diet. Fred
My kidney stone analysis does not seem to say much to me as a patient.
And what does DNR mean in a kidney stone analysis. “Do not resuscitate” does not make sense here, but the internet does not seem to give me clues.
History:
2011: 1st kidney stone, Lithotripsy.
It was treated as a one-off, no follow-ups, not dietary instructions, no warning that more could develop in the future
2021: tiny sensation in lower back for a couple of days, not even real discomfort, just a slight awareness. Felt like a hyperchrondriac to even go the Dr. , 2-week wait to see my doctor, so I saw a PA who ordered an “urgent” CT, took a week to get a doc to sign off on that, had emergency surgery the next day, a huge kidney stone in each kidney. Left kidney no functioning at 6% not addressed because too risky. Right kidney 94%, apparently blockage so temporary stent. 3 weeks later Lithotripsy, but large amount of detritus from lithotripsy. I had asked for a stone analysis so that I could adjust my diet as necessary. The mysterious results follow:
____________________________________________________________________
Details
Past results [Note: No test after my 2011 kidney stone]
Graph of past results
Component results
Component Your value Standard range Flag
Specimen Source RIGHT KIDNEY STONE
Component 1 See Below [Note: Nothing was below]
Component 2 DNR [What does DNR mean in this context?
Stone weight 0.007 gm
gm
General information
Ordered by: XXX XXX, MD
Collected: 08/06/2021 9:40 AM from OTHER
Resulted: 08/13/2021 12:37 AM
Result status: Final result
This test result has been released by an automatic process.
Hi Lois, I think the lab could not determine the composition in that the sample was only 7 mg (0.007 gm) – although it should have been enough. Another possibility is that the part below had a note not sent to you with the information. Your physician would have that. Given you have lost function in one kidney and there was a large stone in the other, I am concerned for you. Take a look at a plan about how to proceed as a kidney stone former. Given only one kidney prevention and urological management is very critical and perhaps your physicians might want to make a referral to a major stone center convenient to you. If you tell me where you live, I can try to help with a suggestion. Regards, Fred Coe
DNR here is Do Not Report
Thank you for helping me interpret the results of my recent 24 Hour Urinalysis by Quest Diagnostics Nichols Institute, below. This specimen was collected one month after I passed the 6mm stone mentioned in my March 3, 2023 response to your “Fluids, Diet, and Meds for Common Stones” page, which the lab identified as Calcium Oxalate Dihydrate (Weddellite) 20% and Calcium Oxalate Monohydrate (Whewellite) 80% (I have a good photo of the stone but was unable to post it).
SPECIMEN VOLUME: Your value 3.34, Standard range >2.00
PH: Your value 6.3, Standard range 5.5 – 7.0
CALCIUM: Your value 189, Standard range <250.0
OXALATE: Your value 31, Standard range <45
URIC ACID: Your value 655, Standard range 320
SODIUM: Your value 97, Standard range <200
SULFATE: Your value 16, Standard range <30
PHOSPHATE: Your value 912, Standard range 60.0
AMMONIA: Your value 43, Standard range 14 – 62
POTASSIUM: Your value 60, Standard range 19 – 135
CREATININE: Your value 1284, Standard range 800 – 2000
CALCIUM OXALATE INDEX: Your value 0.79, Standard range <2.00
BRUSHITE SATURATION FRACTION: Your value 0.93, Standard range <2.00
SODIUM URATE SATURATION FRACTION: Your value 0.49, Standard range <2.00
STRUVITE SATURATION FRACTION: Your value 0.76, Standard range <75.00
URIC ACID: Your value 0.47, Standard range <2.00
24HR URINE STONE RISK COMMENT: No metabolic abnormalities detected.
Below are my notes for reference; this diet and intake are typical following stone diagnosis (previously high oxalates, low calcium, insufficient hydration). Perhaps I can get away with being less strict about oxalate intake?
collection start: 2023-04-08 07:30 (before breakfast)
collection end: 2023-04-09 07:30 (before breakfast)
collected volume: about 1.5" from top of non-graduated container
consumed volume: 3750 ml
~3000ml water with lemon juice throughout day (citrate to bind with calcium in kidneys)
dinner (prior to collection):
half of one homemade pizza
crust: flour (OO, spelt, white whole wheat, wheat, pastry), olive oil, yeast, malt powder, pinch of salt
toppings: tomato sauce, Asiago cheese, onion, bell pepper, capers, oregano, crushed red pepper, fresh arugula
swig of 2% kefir (calcium to bind with oxalates in gut)
evening (prior to collection):
air-popped white corn lightly buttered with pepper
breakfast:
~250ml tea
~250ml coffee with cream
one slice of whole grain sourdough toast with 1/4 of fresh avocado, lightly salted
swig of 2% kefir (calcium to bind with oxalates in gut)
lunch:
second half of pizza described above
swig of full fat kefir (calcium to bind with oxalates in gut)
afternoon:
unsalted tortilla chips and salsa
swig of full fat kefir (calcium to bind with oxalates in gut)
dinner:
roasted cauliflower and broccoli, olive oil, black pepper, lightly salted
swig of full fat kefir (calcium to bind with oxalates in gut)
evening:
air-popped white corn lightly buttered with pepper
night:
~250ml plain water (without lemon juice)
Hi Jim M, Your urine results are all normal, so given this one sample there are no clues as to why you formed stones. A common reason given this is that urine volumes have been substantially lower or diet substantially different in years past and caused stones. Regards, Fred Coe
Hey, Dr Coe.
In reading through the comments above the first gentleman had very similar Urine Volume and Calcium in the 24 hr urine results, but my Brushite saturation is at 2.3 (Quest diagnotstics as well) The only thing I can see is that my PH 7.0 is driving the Brushite saturation. Been working to bring up Citrate (still a little low) but have brought my PH up from 6.2 to 7.0….. Any way to improve Citrate without a corresponding rise in PH?
If I had to choose between reducing my citrate to reduce PH to get my Brushite back in line, Is that a trade worth making?As a note, When my PH was 6.2 with similar volume, by Brushite SS was below 1, which I believe is where I need to be. Calcium OX ss is currently below 1.
Hi Michelle, When citrate is low and stubborn about rising despite a very high urine pH the most plausible cause is one of the renal tubular acidosis genes. Not the full blown disease, often, but having one abnormal version and one normal – heterozygous. The other is drugs that might compromise renal acid excretion. Check all of your meds online and see if any do this. Finally, calcium phosphate stone formers can have this behavior but I think many are heterozygous for renal tubular acidosis. Let me know the answer. Regards, Fred Coe
Thank you for the prompt response. The only medication I take is Hydrocholorothiazide. Any suggestions for a go forward strategy?
Hi Michelle, possibly the OHCTZ is lowering your citrate because of mild potassium depletion – serum values need not be below normal. The drug is very weak for stone prevention. I would drop it in favor of chlorthalidone – perhaps 12.5 mg/d with potassium chloride 20 mEq/d or more. This will protect you better and the KCl may increase your citrate. Ask your physician if he/she thinks this is not unreasonable. Regards, Fred Coe
11 mm kedney stone
Hi Mohd, That is a reasonable size stone and you should have a urologist evaluate your situation. Regards, Fred Coe
I just got my results from the 24hr. urine. I have a history of stones dating back 20 years. Last year, I had stones in both kidneys and bladder. I’ve since moved and knowing my history my Dr. order CT when my Ua showed blood.
Again, stones in both kidneys & bladder. I had suspected BPH which the former urologist said was not a problem. My Dr. now said it was enlarged and we did a TURP with the first Lithotripsy. Not wanting to keep me under too long, we did 2 phases. Litho & TURP, then was to wait a month for next Litho for rest of stones. Unfortunately stones blocked the stent and I would up in ER. So, my second lithotripsy was done a couple of days later.
Since al this, I have increased my fluid intake and eliminated most tea from my diet. I am also a heart failure patient, so had been limiting my fluids. I now realize I limited too much.
My concern is that by increasing the fluids just prior to the 24hr specimen, it may have skewed the results.
From reading your info, I do see that I am prone to stones though.
I would appreciate any thoughts.
CYSTINE, URINE, QUALITATIVE Neg
Negative
URINE VOLUME (PRESERVED) 3,290 mL/24 hr
500 – 4,000 mL/24 hr
CALCIUM OXALATE SATURATION 4.65
6.00 – 10.00 L
CALCIUM, URINE 241 mg/24 hr
450 mg/24 hr L
CALCIUM PHOSPHATE SATURATION 1.60
0.50 – 2.00
PH, 24 HR, URINE 6.769
5.800 – 6.200 H
URIC ACID SATURATION 0.08
<1.00
URIC ACID, URINE 615 mg/24 hr
<800 mg/24 hr
SODIUM, URINE 183 mmol/24 hr
50 – 150 mmol/24 hr H
POTASSIUM, URINE 43 mmol/24 hr
20 – 100 mmol/24 hr
MAGNESIUM, URINE 97 mg/24 hr
30 – 120 mg/24 hr
PHOSPHORUS, URINE 1,060 mg/24 hr
600 – 1,200 mg/24 hr
AMMONIUM, URINE 30 mmol/24 hr
15 – 60 mmol/24 hr
CHLORIDE, URINE 156 mmol/24 hr
70 – 250 mmol/24 hr
SULFATE, URINE 18 meq/24 hr
20 – 80 meq/24 hr L
UREA NITROGEN, URINE 8.00 g/24 hr
6.00 – 14.00 g/24 hr
PROTEIN CATABOLIC RATE 0.6 g/kg/24 hr
0.8 – 1.4 g/kg/24 hr L
CREATININE, URINE 1,406 mg/24 hr
Not Applic. mg/24 hr
CREATININE/KG BODY WEIGHT 11.4 mg/24 hr/kg
11.9 – 24.4 mg/24 hr/kg L
CALCIUM/KG BODY WEIGHT 2.0 mg/24 hr/kg
<4.0 mg/24 hr/kg
CALCIUM/CREATININE RATIO 172 mg/g creat
34 – 196 mg/g creat
Hi Durward, You do not mention what the stones are made of. I presume calcium oxalate. You do not list the 24 hour urine oxalate but I suspect it is high given the SS for CaOx is 4.6 with a urine calcium of only 271 and a volume of 3 liters. More information might make me a better help. Regards, Fred Coe
I just got my results back from my 24 hour urine. They done a stone analysis for my last stone attack in July. As a 55 year old woman, I had never had kidney stones until a year ago and my body started forming them. Since that time, I have had 7 stones, 7 surgical procedures and it has been miserable.
Cystine, Urine, Qualitative Neg
Urine Volume (Preserved) 1,880 mL/24 hr
Calcium Oxalate Saturation 4.02
Calcium, Urine 1 171 mg/24 hr
Oxalate, Urine 1 25 mg/24 hr
Citric Acid (Citrate) 1 180 mg/24 hr
Calcium Phosphate Saturation 1.55
pH, 24 Hour Urine 6.569
Uric Acid Saturation 0.24
Uric Acid, Ur 710 mg/24 hr
Sodium, Ur 142 mmol/24 hr
Potassium, Ur 44 mmol/24 hr
Magnesium, Urine 89 mg/24 hr
Phosphorus, Ur 822 mg/24 hr
Ammonium, Urine 44 mmol/24 hr
Chloride, Ur 138 mmol/24 hr
Sulfate, Ur 42 meq/24 hr
Urea Nitrogen, Urine 11.73 g/24 hr
Protein Catabolic Rate, Ur 0.9 g/kg/24 hr
Creatinine, Ur 1,002 mg/24 hr
Creatinine/Kg Body Weight 10.1 mg/24 hr/kg
Calcium/Kg Body Weight 1.7 mg/24 hr/kg
Calcium/Creatinine Ratio 171 mg/g creat
I drink about 80 or more oz of water a day. I walk 1-2 miles a day. I rarely add any salt to my food. I rarely eat processed or fast food. Trying to determine best course of action on what is causing the stones and what to prevent then. Thank you, Liz
Hi Liz, Your data show no obvious stone forming issues apart from a high pH. You do not mention the stone analysis but it could be calcium phosphate. I suspect you are forming stones for reasons not obvious in these labs. As an example, primary hyperparathyroidism can cause stones in mid-life. Is your fasting serum calcium normal? Perhaps something else, like bone disease with increased bone mineral loss into urine? From here I am afraid I cannot say more. Regards, Fred Coe
My chemical analysis of my stone is below:
Calcium Oxalate Dihydrate (Weddellite) 20%
Carbonate Apatite (Dahllite) 80%
Stone Weight .0005
I don’t believe they have completed a fasting serum calcium test. Thank you for your feedback.
Liz Lewis
Hi Liz, Let me know – out of interest. Fred
Hi Dr. Coe
I’ve produced at least 10 stones in the last 10 years. 5 of those in the last 10 months. We were only able to analyze one and it was calcium oxalate. My first 24 hr urinalysis is back with the below results. Also to note bloodwork came back with elevated liver enzymes, elevated cholesterol (never had cholesterol issues before), elevated DHEA, and elevated A1C. My parathyroid was normal, as well as my blood calcium and vitamin d levels (high normal). I am a type 2 diabetic with an average A1C of 5.6 with meds. I also have IBS and have had malabsorption issues in the past.
Total urine volume 1.52L
PH Urine 7.3 H
Calcium 265 H
Oxalate 115 H
Uric Acid 421
Citric Acid 478
Sulfate 5
Phosphorus 731
Magnesium 40 L
Ammonium 12 L
Potassium 28
Creatinine 1065
Calcium Oxalate 10.42 H
Brushite 6.82 H
Sodium Urate 2.02 H
Struvite 6.03
Uric Acid .07
Hi Corrine, I am concerned by the very high urine oxalate – it is not a simple issue. Your urine magnesium is low, as well. I suspect you do indeed have some form of malabsorption. Likewise your urine sulfate is remarkably low suggesting too low a protein intake or malabsorption. Urine calcium is way too high. The high DHEA is usually related to polycystic ovarian syndrome but your physicians would have noticed this. The low magnesium and sulfate make me worry about either malabsorption or perhaps your diet is abnormal to a serious extent. What ever the underlying issues the high urine oxalate needs to be explained and treated. I presume your physicians have directed themselves to that end and will figure things out. I think it urgent this is accomplished. Regards, Fred Coe
Thank you for your reply. My urologist put me on HCT (I think it’s called) a BP med to help with oxalate. Is having me take calcium with each meal and drink 3 liters of water. He referred me to a nephrologist, and I’m waiting to get in with them. He did mention hypercalicuria and hyperoxaluria. You mentioned “urgent”, is there a time frame I should push for to get in with the nephrologist?
Hi Corrine, Your urine oxalate was rather high. I said urgent because of that. I would get a repeat 24 hour urine rather soon and if the value remains so high – above 100 mg/d if I remember correctly – the thiazide might not be idealThe link is to a case in which urine oxalate was high because of bariatric surgery and diuretics led to kidney injury. But oxalate is the same from whatever cause. I suggest you mention this to your physician for his/her opinion as that person is in charge of your care and I am an outsider who does not really know your medical situation. Regards, Fred Coe
Good morning, Dr. Coe!
I am grateful I found your site. I am currently struggling with my 2nd kidney stone – a 6mm stone in the lower pole of my left kidney. I have been working with my PCP, as I am currently trying to find a urologist in my network. I have a friend who gets chronic kidney stones and found our she has Hyperoxaluria and suggested I try a 24 hour urine collection.
I asked my PCP last week to do this test for me, and she had never heard of it before (neither had the lab tech), and so after they researched it, they ended up finding a Urine Oxalate test and I did my 24hr collect on Sunday, 10/29/23 into Monday, 10/30/23. I just got the result back and it appears the test was not correct.
The test was: *Oxalate, Quant, 24-Hour Urine
Oxalates, Urine 27 Undefined (mg/L)
Oxalates, Urine 24hr 22 4-31 (mg/24 hr)
It looks like they didn’t test for any Creatinine, Calcium, Sodium, or Citrate like you have listed above. I have been having a rough time and I am desperately seeking answers so I can see what my stones are made of and hopefully start preventing them. What is the test called that I should be asking my doctor for? Is there anything you can tell from these results?
Dear Lauren, One needs a comprehensive 24 hour urine panel. The main vandor in the US is Litholink, owned by LabCorp. PHysicians register with LL and their office can order as needed. A simple oxalate is hardly sufficient! Here is a nice summary of how one should be evaluated. If you tell me where you live I can try to identify a kidney stone center who perhaps can help your physicians take care of you. Regards, Fred Coe
My cousin has horrible kidney stones. She did a 48 hr collection and her urine calcium is 766. Her parathyroid is normal. Her doctor prescribed a diuretic and she will have surgery for a stone that is stuck. Looking for help for her. Her urine úric acid is 1.094. Why would her urine calcium be so high?
Hi Janet, The very high urine calcium is hard to understand. Was it for 48 hours? DId she have 2 24 hour urine samples? If so there should be two 24 hour urine calcium levels. Perhaps you are sending the higher of the two? In days gone by before we understood how to do 24 hour collections we did two – one with calcium, oxalate, etc and one with alkali for uric acid. We never do that anymore. Perhaps the lab is one of the old style and not so reliable? Perhaps the urine was over collected – creatinine is helpful here. I would be sure about what was measured and how before involving her in additional studies and before commuting to treatment. IF indeed a correctly done 24 hour urine calcium is above 700 and on two collections, she may well have something unusual and need special care. Regards, Fred Coe
Hi Dr. Coe,
I have been very confused between my 24 hr urine tests and which stones I have. As I have been following the KSD now based on the assumption I have calcium oxalate stones…but if I have calcium phosphate stones I am eating very wrong. As I am eating dairy, chicken and eggs. My urologist has me on potassium citrate and hydrochlorothiazide.
Here are the numbers of my two 24 hr tests 6/2/23. This is after two lithotripsys in February and March 2023 which apparently blasted my numerous stones.
I’m only going to fill in numbers that are high or low.
Test 1 Test 2
Urine volume 2640 2740
Calcium oxalate saturation 2.87 low 2.59 low
Calcium urine 201 high Normal
Urine citrate 483 low 502 low
PH 24 urine 7.487 high 7.376 high
Magnesium, urine 183 high 189 high
Phosphorus, urine 499 low Normal
Ammonium, urine 12 low 13 low
Chloride, urine 62 low Normal
Creatinine 21.5 high 21.4 high
Calcium 4.4 high Normal
I’d appreciate any information as I am eating assuming it’s calcium oxalate stones…but if it’s calcium phosphorus I think I’m eating completely wrong as it says not to eat diary, chicken, eggs…oy
I’m hoping I have not messed things up. Between the eating and the meds I was hoping I was on the right track. But, as I’m always reading I discover that if it’s phosphate stones…I may have made a mistake, and even the meds may be wrong? I have an x-ray coming up in a month and a consult with my urologist. I’m wondering if I should ask for the 24 hr test again before I see him…..
Thank you so much for your wise counsel and time. Much appreciated
Hi Mindy, I guess the stones and crystals were discarded – shame as they could resolve matters. Of course your urine pH is very high, near that of blood, and citrate is not high so the alkali does not seem helpful. But the urine is odd. If the values are mg/d then phosphate is low and chloride is so low I have to presume a very low sodium diet. I do not know the units for creatinine nor 4.4 calcium. You do not give SS for calcium phosphate. Calcium phosphate stone formers have no issues with eating dairy, chicken or eggs, so I do not know where that advice arose – it is plain unsupported by evidence. Regards, Fred Coe
Hi Dr. Coe,
I wrote over a week ago and received only a message that it was waiting moderation. Then my letter disappears, very disappointing…as I still see all the questions before me are still here. I was hoping I would have possibly received an email response but did not at least. So hereI rewrite the entire thing again hoping for an answer. I have had multiple kidney stones diagnosed on both kidneys. I ended up in Feb/March having lithotripsy’s on both kidneys. I then had an Xray that showed only gravel….but my 24 hr urine test has me a bit confused as I am not sure if I have calcium oxalate, or calcium phosphorus stones as it seems the diets are different and I have been doing the diet for oxalate stones. My urologist said I had calcium stones….but, um there seems to be a dietary difference between the two types and I certainly do not want yo end up with stones again.
So here is the result of my 2 24 urine tests.
I will write in only those numbers that are high or low for the two tests side by side. I would like to know if you think I should ask for another 24 urine before I see him this December 22. I am having another X ray December 11th.
Litho link panel 24 hr
6/7/23
Urine volume Test 1. 2640. Test 2 2740
Calcium oxalate saturation 2.87 low. 2.59 low
Calcium urine. 201 high 155 normal
Citrate urine. 483 low. 502 low
Ph 24 urine. 7.487high. 7.376 high
Magnesium urine. 183 high. 189 high
Phosphorus urine. 499 low. 630 normal
Ammonium urine. 12 low. 13 low
Chloride urine 62 low. 73 normal
Creatinine kg body weight. 21.5 high. 21.4 high
Calcium kg body weight. 4.4 high. 3.4 normal
My urologist has me on potassium citrate and hydrochlorothiazide. He told me no tea, drink lots of water and no sodium. I have taken it upon myself to go on the KSD and watch my oxalates. Please advise me what type of stones it seems I make here and if I’m on the right diet, or do I avoid meat, dairy and eggs because of phosphorous stones. I am confused all over agin.
Thank you again and for your advice
Hi Mindy, I am sorry about the delay. I answered your first question. Once again, diet treatment for CaOx and CaP stones do not differ that I know of. It is in the use of alkali treatment most differs. I notice your physician mentioned ‘calcium’ stones so perhaps she/he had an analysis result. Perhaps you have some crystals or stones still at home in a drawer – they are stable for decades and can be analysed at any time. Regards, Fred Coe
Thank you so much for the response. I’m sorry, I never received the first answer, not do I see it anywhere in this blog. So, I assume, I should just keep going as I’m going and eat the KSD. I have no crystals or any pieces from my blasting. I never caught anything….
Next month I get an x-ray and I am praying all is clear, and that I am just doing the right thing based on my Dr, you, and Jill Harris. Thank you again, and have a blessed Thanksgiving.
Hi Dr. Coe,
I had a large kidney stone broken up a year ago August, and have been diligent since then to drink enough water. I drink 8 ounces of water every time I sweat or pee, and 8 – 10 ounces at every meal. In addition, I will sometimes drink 8 ounces randomly during the day, especially if I have been out somewhere and not had easy access to water. Needless to say, this has changed my habits when it comes to the bathroom. I was concerned this year because I was passing small (about 1mm – 1.5mm) stones on a regular basis, about once a week, sometimes more, sometimes less. I visited my urologist, who recommended the 24 hour collection, the results are her. I have not spoken with him as yet, but found your website with a lot of very good information that has educated me more than my previous research on this.
The day of the test I stayed home all day so that I could collect the urine easily. This led me to drink more water than usual, as I adhered to the above regimen strictly, and it was evident to me that I was drinking more water than usual. I think it is likely that in normal circumstances I drink 2 to 2.5 liters a day.
I’ve tried to understand my test results after studying your website, but don’t completely understand what might be my best course of action. I am mostly vegetarian, with some fish and chicken occasionally, and drink tea and/or chocolate drink in oat milk every morning. Any advice or insights will be much appreciated.
Cystine, Urine, Qualitative Neg
Urine Volume (Preserved) 4380 mL/24 hr
Calcium Oxalate Saturation 1.91
Calcium, Urine 91 mg/24 hr
Oxalate, Urine 44 mg/24 hr
Citrate, Urine 1084 mg/24 hr
Calcium Phosphate Saturation 0.2
pH, 24 hr, Urine 6.424
Uric Acid Saturation 0.1
Uric Acid, Urine 488 mg/24 hr
Sodium, Urine 117 mmol/24 hr
Potassium, Urine 63 mmol/24 hr
Magnesium, Urine 89 mg/24 hr
Phosphorus, Urine 644 mg/24 hr
Ammonium, Urine 20 mmol/24 hr
Chloride, Urine 108 mmol/24 hr
Sulfate, Urine 20 meq/24 hr
Urea Nitrogen, Urine 6.19 g/24 hr
Protein Catabolic Rate 0.7 g/kg/24 hr
Creatinine, Urine 1276
Creatinine/Kg Body Weight 16.5 mg/24 hr/kg
Calcium/Kg Body Weight 1.2 mg/24 hr/kg
Calcium/Creatinine Ratio 71 mg/g creat
Hi Rives, your comment is your answer but that is not obvious. The collection was at home and fluids were higher than usual. Your volume was above 4 liters/d and stone risk absent. You estimate it would be 1/2 that on usual days. But also, it will vary from hour to hour. Diet may vary as well. You do not mention your stone type, which matters very much. I would collect again on two working days to find out what is really happening. That large stone did not form in the urine presented here – could not. Regards, Fred Coe
The stone that was removed was an oxalate stone. What I was trying to derive from my test results was how much water I would need to drink to remove 44mg of oxalates in a day, as it appears that the 4380 ml was more than enough, as the oxalate concentration was flagged low, but the total oxalates was flagged high. Would about 2 to 2.5 liters of water be enough to remove this quantity of oxalates without having an oxalate concentration high enough to form stones? I ask because as I said I do pass small stones from time to time, and am wondering if maybe I am not having enough water on those days, or if there are other ways I can modify things to be sure I don’t form a big stone again.
Hi Rives, I went back to review your comment and my answer. One does not titrate oxalate by urine volume. Crystals can only sense supersaturation which is the product of calcium times oxalate concentrations. Supersaturation refines that idea adding important details. Your urine of more than 4 liters a day will not produce calcium oxalate crystals. At 1/2 that volume SS for CaOx would be about 4 – 5, that for CaP – very important in igniting stone formation – would still be below 1. Yet you formed and continue to form crystals and stones that are said to be calcium oxalate. Possibly in real life you have periods where hourly urine flow is far lower than the 2.8 ml/minute implied by your 4 liter collection (4000 ml/1440 minutes/day). That could cause spikes of saturation high enough to create crystals which once formed will not dissolve. Possibly the stone analysis is not in fact calcium oxalate alone but a mixture of other crystals. I do not know enough about you to say more, but I am quite convinced there are details what are crucial in understanding stone formation in your situation. Regards, Fred Coe
Hi Dr. Coe,
Thank you for such valuable information. I have chronic stones and my urologist finally ordered a 24hr urine test.
My 24hr results were:
Cystine, neg.
Volume 2800mL
Calcium Oxalate Saturation 2.33, LOW
Calcium 95mg
Oxalate 14mg, LOW
Citrate 493mg, LOW
Calcium Phosphate Saturation 0.95
PH 6.921, HIGH
Uric Acid Saturation 0.06
Uric Acid 400mg
Sodium 70mmol
Potassium 17mmol, LOW
Magnesium 40mg
Phosphorus 425mg, LOW
Ammonium 17mmol
Chloride 58mmol, LOW
Sulfate <6mmol, LOW
Urea Nitrogen 3.43g, LOW
Protein Catabolic Rate 0.5 LOW
Creatinine 957mg
Creatinine/KG Body Weight 13.6mg
Calcium/KG Body Weight 1.4
Calcium/Creatinine Ratio 99mg/g
Hi AM, Your results are odd indeed. You weigh about 70 kg (154 pounds but have a very low creatinine (muscle mass) for your wright 13.6 mg/kg usually meaning obesity or malnutrition. Your urine is more consistent with the latter than the former because key nutrients such as potassium (17 meq), urea nitrogen (protein intake) gives about 0.5 gm protein/kg body weight daily which is below acceptable for health. Although your acid load from food – urine sulfate – is below the lower limit of measurement (<6 mEq) your urine ammonia is not low at 17, and I take this to be a result of potassium insufficiency. The urine is alkaline with pH of 6.9 because of absent acid and high ammonia which all may be from potassium deficiency. Altogether things look very complex and beyond what I can help with, but unless the urine is very undercollected – giving false low readings – you seem to have either an important diet issue or unsuspected malabsorption – matters far beyond what I can analyse from here. Quite possibly the urine is simply misleading from undercollection as urine oxalate is abnormally low. Regards, Fred Coe
Thank you for your reply. I appreciate your time.
Hello Dr. Coe,
I hope this finds you in good spirits. I am so glad someone like you exists to help others with this issue. I recently had my 2nd stone after close to five years. It was very small (punctate it was called) but it gave me hell and I ended up in the ER. My first one was the same but never saw that one on the CT, just the aftermath.
So, I just did a 24-hour test and if I’m reading the results correctly, it seems I’m low in citrate, potassium, and magnesium.
My sister has Gitleman’s syndrome, so I dont know if that’s helpful. She has had it all her life and passes a lot of stones frequently. We are both in our 40s–though my first one was at 45 and the 2nd at 49. But I’ve never been tested for it now doing some research, might I have a mild case?
Hoping you can shed some light.
Thank you!
Vol 24 – 3.76
SS CaOx – 2.49
Ca 24 -170
Ox 24 -23
Cit 24 – 479
SS CaP – 0.56
pH – 6.772
SS UA – 0.04
UA 24 – 0.355
Na 24 – 82
K 24 – 29
Mg 24 – 63
P 24 – 0.404
Nh4 24 – 28
Cl 24 – 97
Sul 24 – <11
UUN 24 – 0.5
Cr 24 – 872
Cr 24/Kg – 15.4
Ca 24/Kg – 3.0
Ca 24/Cr 24 – 195
PCR – 0.5
Hi Natalie, Your results are interesting. Your PCR of 0.5 means 0.5 gm protein/kg body weight/day which is very low – in the range of malnutrition. Accordingly your acid intake measured by sulfate is <11 meaning below the limits of the test system. But your ammonia, which is the response to acid load is not low but 28, a middle normal value. This picture is most common with very low protein diets and mild potassium deficiency – your urine potassium is low normal. The high urine pH and reduced citrate are what one expects with reduced body potassium stones, whereas low protein diet alone would give a very high citrate because there is so little acid load. Possibly you have a diet that is not ideal for you, a matter your physician can unravel. But also possibly you have a CLC – kb mutation which is affecting potassium handling. I say this because your sister has Gitelman syndrome one version of which involves that channel – you would be heterozygous. None of that would explain your very low protein diet which seems an independent matter. In all, my comments are not helpful except possibly your physicians might want to consider them in light of their much greater knowledge of your situation. Regards, Fred Coe
My kidneys’ ultrasound test has detected kidney stones. I also have second stage CKD.
The following is the result of the 24-hour urine test, which was ordered to determine the composition of those stones.
Cystine, Urine, Qualitative Neg Negative
Urine Volume (Preserved) 3290 mL/24 hr 500-4000
Calcium Oxalate Saturation 1.00 Low 6.00-10.00
Calcium, Urine 50 mg/24 hr 450
Calcium Phosphate Saturation 0.09 Low 0.50-2.00
pH, 24 hr, Urine 5.893 5.800-6.200
Uric Acid Saturation 0.53 <1.00
Uric Acid, Urine 693 mg/24 hr <800
Sodium, Urine 187 High mmol/24 hr 50-150
Potassium, Urine 91 mmol/24 hr 20-100
Magnesium, Urine 122 High mg/24 hr 30-120
Phosphorus, Urine 1178 mg/24 hr 600-1200
Ammonium, Urine 51 mmol/24 hr 15-60
Chloride, Urine 204 mmol/24 hr 70-250
Sulfate, Urine 46 meq/24 hr 20-80
Urea Nitrogen, Urine 13.90 g/24 hr 6.00-14.00
Protein Catabolic Rate 1.1 g/kg/24 hr 0.8-1.4
Creatinine, Urine 1623 mg/24 hr Not Applic.
Creatinine/Kg Body Weight 17.9 mg/24 hr/kg 11.9-24.4
Calcium/Kg Body Weight 0.6 mg/24 hr/kg <4.0
Calcium/Creatinine Ratio 31 Low mg/g creat 34-196
What is confusing is that Calcium Oxalate Saturation and Calcium Phosphate Saturation levels are low, but these are, apparently, the substances that most commonly form the stones. Or it is just the opposites – their levels decrease with the formation of stones.
Also, based on this report – which foods should be avoided and, on the opposite side, included in the diet? Lowering sodium intake seems to be obvious…
Thanks in advance
Hi Boris, I can understand your confusion. Stones were seen on ultrasound under conditions of urine chemistry such that one must wonder how crystals might form. ONe answer is the ultrasound – only 50% or so sensitive and equally specific. I suspect it is over reading. You do not give urine oxalate so I must assume it is not high. The urine volume is so high I presume you have raised your fluid intake, and perhaps in times past volume was low. Given the pH is 5.8 a large fall in urine volume could easily have created uric acid SS so stones could be uric acid. I suggest a kidney stone CT, low radiation machine and protocol, and if stones are found measure the Hounsfield units to see if it is low – uric acid. Regards, Fred Coe
Hi Dr. Coe,
I’m a 52yo woman. History of hypertension and currently taking 25mg clorthalidone and 20mg Lisinopril, blood pressure well controlled.
I also take Magnesium glycinate 240 mg/day, Magnesium malate 250 mg/day, vitamin D 2000 IU every other day, calcium 1010 mg/day.
I had lithotripsy about a year ago to break up a 1cm stone.
Just got my 3rd 24hour test and bloodwork results and hoping for your insight. My urine calcium and calcium phosphate saturation has gone up since my prior tests.
Volume: 1680
Calcium Oxalate Sat 6.95
Urine Calcium 408
Urine Oxalate 29
Urine Citrate 838
Calcium phosphate Sat 2.27
pH 5.805
Uric Acid sat 1.00
Uric Acid Urine 586
Urine Sodium 133
Urine Potassium 65
Urine Magnesium 273
Urine Phosphorous 1587
Urine Ammonium 38
Urine Cloride 137
Urine Sulfate 34
Urine Urea Nitrogen 9.09
Protein catabolic rate 0.9
Urine Creatinine 1716
Creatinine/kg body weight 21.0
Calcium/kg body weight 5.0
Calcium/creatinine ration 238
Hi Christine, Your urine calcium is quite high despite the medication and a reasonable urine sodium. Given the urine volume is not very high CaP SS is above 2 causing a high stone risk. I notice a high urine phosphate, usually this arises from cola or other beverages or even foods supplemented with phosphates – that worsens stone risk. Of course I do not know anything about your serum values or general medical condition but a much lower diet sodium might help with urine calcium and blood pressure. I presume serum calcium is normal – even a slight increase is important here. Regards, Fred Coe
Thank you Dr. Coe. The lab seems to have lost my blood from my most recent visit as they did draw blood when I took the 24 hour urine test in, but did not include the results in my lab report. In the 2 prior blood tests in January and April, serum calcium was 9.8 and 9.4, respectively. I do not drink cola. I generally drink a coffee in the morning, water during the day, and occasionally red wine with dinner. I usually try to drink a lot of water. (The day of my collection was on a day when I was busy with post-Thanksgiving clean-up, so I wasn’t carrying my water bottle around with me. Prior test urine volumes were 2.19 and 2.23L, and I have been trying to increase water intake per my nephrologist’s recommendation.
I am generally in pretty good health. I work out by riding a Peloton bike at least 4 days a week. I have been taking Wegovy for the past year and a few months. I was overweight, but Wegovy helped me lose over 40 pounds. While I am still a bit overweight and hit a plateau, I don’t believe I am obese. Could the Wegovy be causing the high phosphorous and calcium levels? Should I stop taking or reduce the calcium supplement?
Hi CHristine, Urine volume varies rapidly with water balance. Crystals form whenever they can and do not dissolve. That is why water is not a good solitary stone prevention. The serum calcium results make hyperparathyroidism unlikely. The source of the high urine phosphate remains unexplained but is coming from additives – any processed foods will do it. As for specific advice – diet calcium for example – I would be doing you an injustice to say as I do not know enough about your medical situation – that is for your physicians. Regards, Fred Coe
Hi Dr Coe,
I had stones years ago and recently had a few more. Did testing this time. I was what I thought a healthy 39 yo F. (The beginning of this year I was diagnosed with POF/POI. They beleive it to be autoimmune based on them finding low level of TPO antibodies, normal functioning thyroid as of now.) I began HRT.
Following my recent diagnosis of POF I had recurrent UTIs (every 2 weeks for 4-5 months) which led to the discovery of the stones. As far as we know they are all passed after the last caused ER overnight hydronephrosis, passed on my own the next day.
My stone composition:
Calcium Oxalate Monohydrate (Whewellite) 95%
Carbonate Apatite (Dahllite) 5%
Litholink
My 48 hr urine test (24 and 24 hr)
Cystine: neg
Volume: 2550 2640
Cal. ox. sat: 2.55 LOW 2.32 LOW
Calcium: 170 189
Oxalate: 23 18 LOW
Citrate: 612 650
Cal phos sat: 0.61 0.83
pH: 6.586 HIGH 6.596 HIGH
Uric acid sat: 0.14 0.11
Uric acid: 580 483
Sodium: 188 HIGH 103
Potassium: 56 46
Magnesium: 115 142 HIGH
Phosphorous: 465 LOW 503 LOW
Ammonium: 43 39
Chloride: 218 113
Sulfate: 31 26
Urea Nitrogen: 7.63 7.77
Protein cat rate:1.2 1.2
Creatinine: 906 992
Creatine/Kg: 18.8 20.6 HIGH
Calcium/kg: 3.5 3.9
Cal creat ratio: 188 1.91
They referred me to nephrology, which I have not seen yet, for evaluation for dRTA, I guess due to pH.
I was wondering your thoughts. I have always had low normal serum calcium and a low (slightly below normal) serum osmolarity calculation. I questioned the os Calc to docs and they’ve always told me it’s nothing. (I was not hydrating well during those tests which is why I thought it was strange) I’m hydrating much more since the recent stones.
Thank you in advance for any thoughts
Hi Maggie, your COM stones are not caused by your higher urine pH directly but possibly the higher pH is seeding the stones through brushite when urine volume falls.Your urine calcium is a bit high per mg creatinine the rest of your stone risk factors are benign. I would guess the stones are occurring because of periods of reduced urine flow rate during the course of life and that a bit lower urine calcium (reduced diet sodium) might help in prevention. As for the serum calcium, you do not show it or serum PTH and 25D that might help explain matters. I see no evidence for RTA. Urine pH in women runs higher than in men. Regards, Fred Coe
Dr Coe – I have an appt next week with my Dr, but would greatly appreciate any insight you can provide on my recent lab report. I’m a 54 yr old male. Exercise frequently. No significant health issues. Try to follow a low sodium/fat diet, but clearly I have some changes to make! I do have BPH. I have had 2 kidney stones. Labs on one was a 16 mg calcium oxalate monohydrate. Thank You!
These were low:
Calcium Oxalate Saturation 4.44 L
Calcium Phosphate Saturation 0.28 L
pH, 24 hr, Urine 5.518 L
These were high:
Uric Acid Saturation 3.35 H
Uric Acid, Urine 1571 H
Sodium, Urine 247 H
Potassium, Urine 108 H
Phosphorus, Urine 1691 H
Sulfate, Urine 97 H
Urea Nitrogen, Urine 25.52 H
Protein Catabolic Rate 2.1 H
Creatinine/Kg Body Weight 28.6 H
Oxalate, Urine 52 H
Full results:
Litholink 24-hour urine panel. Includes Cystine Screen
Cystine, Urine, Qualitative Neg Negative
Urine Volume (Preserved) 2060 500-4000 (mL/24 hr)
Calcium Oxalate Saturation 4.44 L 6.00-10.00
Calcium, Urine 135 450 (mg/24 hr)
Calcium Phosphate Saturation 0.28 L 0.50-2.00
pH, 24 hr, Urine 5.518 L 5.800-6.200
Uric Acid Saturation 3.35 H <1.00
Uric Acid, Urine 1571 H <800 (mg/24 hr)
Sodium, Urine 247 H 50-150 (mmol/24 hr)
Potassium, Urine 108 H 20-100 (mmol/24 hr)
Magnesium, Urine 78 30-120 (mg/24 hr)
Phosphorus, Urine 1691 H 600-1200 (mg/24 hr)
Ammonium, Urine 57 15-60 (mmol/24 hr)
Chloride, Urine 237 70-250 (mmol/24 hr)
Sulfate, Urine 97 H 20-80 (meq/24 hr)
Urea Nitrogen, Urine 25.52 H 6.00-14.00 (g/24 hr) The UUN result was verified by repeat analysis.
Protein Catabolic Rate 2.1 H 0.8-1.4 (g/kg/24 hr)
Creatinine, Urine 2397 Not Applic. (mg/24 hr)
Creatinine/Kg Body Weight 28.6 H 11.9-24.4 (mg/24 hr/kg)
Calcium/Kg Body Weight 1.6 <4.0 (mg/24 hr/kg)
Calcium/Creatinine Ratio 57 34-196 (mg/g creat)
Hi John, the urine is over collected. Urine creatinine is 28.6 mg/kg body weight. Such a massive preponderance of muscle is seen only in the rarest athletes and though you are fit by report the ratio points to Olympic style fitness. Over collection also fits with the protein intake of 2.1 gm/kg which only happens with overwhelming excess of meat intake. So I would repeat the collection and not accept this one as valid. Regards, Fred Coe
Hi Dr. Coe,
I’m writing on behalf of my wife, 36, 130 lbs, overall good health. She had a 6mm stone in December that remained in her kidney and had lithotripsy to break it up that was successful. She does have family history of kidney stones, but one of the interesting things that came up was after analysis of her stones, it was determined to be 90% calcium phosphate vs 10% calcium oxalate. Below are the details from her 24hr panel.
Cystine, Urine – Neg
Urine Volume – 3010
Calcium Oxalate Saturation – 5.75
Calcium, Urine – 290
Oxalate, Urine – 53
Citrate, Urine – 1058
Calcium Phosphate Saturation – 1.65
pH, 24hr, Urine – 7.1
Uric Acid Saturation – 0.05
Uric Acid, Urine – 831
Sodium, Urine – 173
Potassium, Urine – 70
Magnesium, Urine – 249
Phosphorus, Urine – 697
Ammonium, Urine – 22
Chloride, Urine – 164
Sulfate, Urine – 34
Urea Nitrogen, Urine – 11.74
Protein Catabolic Rate – 1.5
Creatinine, Urine – 1455
Creatinine/kg Body Weight – 25.1
Calcium/kg Body Weight – 5.0
Calcium/Creatinine Ratio – 199
I know there was discussion of potentially looking at RTA, but not sure if these numbers point to that or not. Even though her family has a history of stones, none have been diagnosed with this.
Thank you so much for any guidance and insight you can provide.
Hi Jeff, dRTA is not likely based on the testing you have shown me – I assume blood tests all are in the normal ranges. The high urine pH is with a high urine citrate whereas with dRTA citrate is universally low. The urine seems over collected as the ratio of creatinine (muscle mass) to body weight of 25.1 is very unusual in a woman except for those especially (remarkably) fit. Even so, the citrate will be quite high. The cause of her stone is at least in part her high urine calcium and the high pH way well reflect that trait’s common association with simply being a young woman. The reason for high alkali absorption by younger women is unknown but its presence is undeniable. As a result hypercalciuric women frequently produce calcium phosphate stones. As in all patients I would recommend a full evaluation and prevention based on the results. Regards, Fred Coe
Hi Dr Coe,
Thanks for all you insight Any advice on the following lab results? What is the cause of my stones and what are ways to help minimize them in the future? Thank you!
Calcium Oxalate Saturation: 4.44
Calcium, Urine 123
Oxalate, Urine: 36
Citrate, Urine: 446
Calcium Phosphate
Saturation: 0.90
Ph Urine: 6.263
Uric Acid Saturation: 0.69
Uric acid Urine: 1005
Sodium, Urine: 175
Potassium, Urine: 64
Magnesium, Urine: 70
Phosphorus, Urine: 999
Ammonium, Urine: 38
Chloride, Urine: 152
Sulfate, Urine: 63
Urea Nitrogen, Urine: 13.8
Protein Catabolic Rate: 1.3
Creatinine, Urine: 1797
Creatinine/Kg Body Weight: 22.6
Calcium/Kg Body Weight: 1.6
Calcium creatinine ratio: 69
Hi Omid, None of the results in your urine point to a reason for stone production. But I presume you made stones. This leaves 24 hour urine volume, which may be low or have been low in the past when you made stones – not a rare situation. Regards, Fred Coe
Urine calcimum ( mg per day) =395
SSCAP = 2.19
24 hour urine PH = 6.723
Hi Shubhendu, You have very elevated urine calcium whose cause needs to be determined so treatment can be offered. Regards, Fred Coe
Calcium Oxalate Saturation 3.09
Calcium urine 395
Calcium Phosphate Saturation 2.19
pH, 24 hr, Urine 6.723
Sodium, Urine 174
Potassium, Urine 108
Magnesium, Urine01 178Phosphorus, Urine 1455
Ammonium, Urine01 66
Urea Nitrogen, Urine 17.86
Protein Catabolic Rate 1.7
Calcium/Kg Body Weight 5.5
Calcium/Creatinine Ratio 225
had a history of calcium oxalate stones in 2021, got my 24 hour urine done in 2024 feb. Pls review and suggest changes in diet, meds etc sir. When should i repeat this?
Hi Shubhendu, I answered about the one number now I have more. Your urine calcium is very high, sodium as well, protein catabolic rate is very high at 1.7 gm protein intake/kg/d. The high protein intake will elevate your urine calcium and is far above the needs for health. If you lower it to 1 gm/kg/d your urine calcium will fall, perhaps into the normal range. If not, you may have idiopathic hypercalciuria, which is a cause of kidney stones and bone disease. Regards, Fred Coe
Hello Dr. Coe,
Can you please explain what “calcium oxalate saturation” means in relation to stone formation. Does a low result mean calcium and oxalate’s are not binding together and being excreted, or does it point to a lower stone formation risk?
Thank you for all of your answers/insight into kidney stone formation.
Hi Adam, saturation is the free energy of crystallization so higher values mean higher stone risk.It is the place where everything combines into one risk number that itself rests on thermodynamics. We calculate is from a set of 24 ion combinations using 24 hour urine data – Litholink is best at this. Calcium oxalate and calcium phosphate SS matter, the latter more than the former. Best, Fred Coe
Urine volume 2350
Calcium Oxalate sat 10.05
Calcium urine 541
Urine oxalate 41
Urine creatine 1602
Calcium Phosphate sat. 2.76
PH 6.299
Uric Acid sat .32
Uric acid 676
Sodium 169
Potassium 56
Magnesium 140
Phosphorus 982
Ammonium 38
Chloride 156
Sulfate 32
Urea Nitrogen 8.52
Protein Catabolic Rate .9
Creatinine 1754
Creatinine/Kg Body Weight 22.7
Calcium/Kg Body Weight 7
Calcium/Creatinine Ratio 308
Calcium Oxalate Monohydrate10 %
Calcium Oxalate Dihydrate 90%
I have an appointment to discuss this with urologist in a week. Trying to be educated before the appointment. Im on Allopurinol for uric acid stones and were well controlled until recently. My stone composition must have abruptly changed?
Hi Jeff, You have a remarkably high urine calcium whose origin is not obvious. Is your blood calcium normal? Your stone is typical of those that form when urine calcium is very high. I would presume it is idiopathic hypercalciuria if there are no other abnormalities.But with so high a value your physicians need to look for systemic causes as well. Best, Fred Coe
New blood tests. Calcium 10.1, Phosphorus 5.0. It seems this ratio is off. High Phosphorus should lower my calcium? PTH 25.2, TSH 3.037, Uric Acid 3.6. I take Allopurinol. Thyroglobulin AB 40, Thyroid Peroxidase AB 98.56. This looks like parathyroid and Thyroid issues.
Hi Jeff, very high urine calcium, borderline high serum calcium, high serum phosphate, lowish PTH. I would get a 1,25 vitamin D test if your physician agrees because you mahe a condition leading to too high a value of this hormone. It is not the common 25D it is 1,25D. Regards, Fred Coe
Hi Dr. Coe,
Thank you for this information, it has been helpful in reading my report. I’m a 44 y/o female with a history of stones in both kidneys from the age of 25. I’ve had 2 surgeries, a basket stone removal of a 6mm stone in 2017 and a lithotripsy of a 5mm stone in 2023, both in the left kidney. I also have IBS since I was a child. Could you give me some advice on my lab results from last year:
Urine Volume .83
SS CaOx 10.90
Urine Calcium 122
Urine Oxalate 34
Urine Citrate 662
SS CaP 2.58
24 Hour Urine pH 6.656
SS Uric Acid .33
Urine Uric Acid .545
Na 24 172
K 24 35
Mg 24 59
P 24 .562
Nh4 24 22
Cl 24 139
Sul 24 32
UUN 24 8.17
PCR 1.1
CR 24 1325
Cr 24/Kg 23.6
Ca 24/Kg 2.2
Ca 24/Cr 24 92
Thank you!
Hi Vicotria, I think your answer is in the volume. If I read it right it is 0.82 liters in a day. That volume is a prime cause of stones.Your daily excretions of stone forming salts are normal but at such a low urine volume crystal formation is very likely. A much higher volume is your treatment. The linked article points out the difficulties and importance of achieving this goal. Regards, Fred Coe
Hello, my stone analysis report states that my stone is 0.01 g. It does not state the size in mm, do you know how many millimeters a stone would be if it is 0.01 g? Thanks!
Hi Robert, I am afraid I cannot do that calculation as I do not know the composition and therefore the density of the stone. But more important than size is composition so stone analysis is very important. Regards, Fred Coe
Hi Dr. Coe,
Really appreciate all the time you take to respond to us. I’ve passed two stones over the past two years, with the last one retrieved characterized as calcium oxalate and several more shown in both kidneys. I’m trying to make changes to stop the formation of more stones. I’m 6′ 215 lbs. Borderline high blood calcium (10-10.2mg/dL) with low PTH (13 pg/mL). No recent vitamin D test, but was low in reading 4 months ago.
I just got my first 24h urine test with a number of results out of range:
Cysteine: Neg
Urine volume 3480 mL
Calcium Oxalate saturation: 5.14 L
Calcium, Urine (mg/24h): 357 H
Oxalate, Urine (mg/24h): 44 H
Citrate, Urine (mg/24h): 536
Calcium Phosphate Saturation: 1.66
pH, 24h, Urine: 6.492 H
Uric acid saturation: 0.19
Uric acid, urine (mg/24h) 868 H
Sodium, Urine (mmol/24h): 150
Potassium, Urine (mmol/24h): 74
Magnesium, Urine (mg/24h): 167 H
Phosphorous, Urine (mg/24h): 1270 H
Ammonium (mmol/24h): 47
Chloride (mmol/24h): 157
Sulfate (meq/24h): 49
Urea nitrogen (g/24h): 12.65
Protein Catabolic Rate (g/kg/24h): 1
Creatinine (mg/24 h): 2226
Creatinine/Kg body weight (mg/24h/kg): 22.8
Calcium/Kg body weight (mg/24h/kg): 3.7
Calcium/Creatinine Ratio (mg/g creat): 161
I’m confused about the collection of high readings. I’m suspicious that the volume reported was wrong–could this lead to systematic high readings? I might also push for a blood test for PTHrP to rule out anything malignancy related.
Thanks very much!
Hi Russ, Your urine calcium is high and PTH low and blood calcium a bit high. The urine looks better to me than to you. The volume (this is Litholink I think) is calculated from dilution of an additive in the preservative your put in and was close enough to your estimate that the company accepted the sample. THe whole picture suggests a primary increase in 1,25 vitamin d (your low vitamin D was 25D) and I would get the former measured. If high you may have a gene abnormality involving CYP 24 and treatment can be specific to that issue. PHOSPHATE FOR CALCIUM KIDNEY STONE PREVENTION Regards, Fred Coe
Hi Dr Coe,
I am a 45 yr old female with first known passing stone at age 30 while pregnant. Scans have only shown stones in L kidney. Getting a cystoscope on 4/5/24 and MD want to do litho after for current stone 5 mm. Thank you for any info!!
Cystine, Urine, Qualitative- Neg
Urine Volume (Preserved)- 2510 mL/24 hr 500-4000
Calcium Oxalate Saturation- 3.55 6.00-10.00 Low
Calcium, Urine- 273 mg/24 hr 550
Calcium Phosphate Saturation- 1.78 0.50-2.00
pH, 24 hr, Urine- 6.590 5.800-6.200. High
Uric Acid Saturation- 0.15 <1.00
Uric Acid, Urine- 634 mg/24 hr <750
Sodium, Urine- 194 mmol/24 hr 50-150 High
Potassium, Urine- 59 mmol/24 hr 20-100
Magnesium, Urine- 113 mg/24 hr 30-120
Phosphorus, Urine- 946 mg/24 hr 600-1200
Ammonium, Urine- 36 mmol/24 hr 15-60
Chloride, Urine- 173 mmol/24 hr 70-250
Sulfate, Urine- 39 meq/24 hr 20-80
Urea Nitrogen, Urine- 10.07 g/24 hr 6.00-14.00
Protein Catabolic Rate- 1.1 g/kg/24 hr 0.8-1.4
Creatinine, Urine- 1294 mg/24 hr Not Applic.
Creatinine/Kg Body Weight- 19.7 mg/24 hr/kg 8.7-20.3
Calcium/Kg Body Weight- 4.1 mg/24 hr/kg <4.0. High
Calcium/Creatinine Ratio- 211 mg/g creat 51-262
Hi Virginia, You have a high urine calcium (above 200 mg raises stone risk) and a high pH (alkaline urine) which fosters calcium oxalate and calcium phosphate stones. This is a genetic condition called idiopathic hypercalciuria. Serum must be evaluated as well – here is a good guide. You have rather high urine (diet) sodium intake near 200 mEq/d and would be best off with 1/2 that. There are other factors as well that your physicians can detail for you. REgards, Fred Coe
Dr Coe,
Thank you for your response. My urologist prescribed me HCTZ 12.5 mg daily and wants me to retake another 24 hr urine in one month. He also said to increase my sodium intake which i didn’t understand.
Hi Virginia, I suspect he meant reduce your diet sodium. Perhaps you might want to ask him/her to clarify. Fred
Hi Dr. Coe,
As a PH3 patient (diagnosed via genetic analysis) – Thank you for this wonderful resource and all of your help!
My 24/hr collection results are as follows, would be very grateful for your read. I am a 34 yr old male, 5’7 and 150 pounds. Generate huge number of calcium oxalate stones.
Urine Volume (Preserved) 2440 mL/24 hr [4.11 previous test]
Calcium Oxalate Saturation 5.69 Low [6.49 on previous test]
Calcium, Urine 192 (mg/24 hr) [165 on previous test]
Oxalate, Urine 49 High (mg/24 hr) [117 on previous test]
Citrate, Urine 906 (mg/24 hr) [1030 on previous test]
Calcium Phosphate Saturation 1.44 [0.32 on previous test]
pH, 24 hr, Urine 6.805 High [6.410 on previous test]
Uric Acid Saturation 0.12 [0.24 on previous test]
Uric Acid, Urine 758 (mg/24 hr) [1.067 on previous test]
Sodium, Urine 130 (mmol/24 hr)
Potassium, Urine 88 (mmol/24 hr)
Magnesium, Urine 115 (mg/24 hr)
Phosphorus, Urine 869 (mg/24 hr)
Ammonium, Urine 39 (mmol/24 hr)
Chloride, Urine 121 (mmol/24 hr)
Sulfate, Urine 55 (meq/24 hr)
Urea Nitrogen, Urine 13.06 (g/24 hr)
Protein Catabolic Rate 1.3 (g/kg/24 hr)
Creatinine, Urine 1519 (mg/24 hr)
Creatinine/Kg Body Weight 21.2 (mg/24 hr/kg)
Calcium/Kg Body Weight 2.7 (mg/24 hr/kg)
Calcium/Creatinine Ratio 126 (mg/g creat)
Hi Dr Coe
Thank you so much for this information and and helping interpret my results. I am a 34 year old male with a kidney stone detected by ultrasound. I had a previous which I passed in 2021. I am also taking 300 mg zonisamide per day and wondering if this could have an effect.
Height: 5′ 8″
Weight: 158
Here are my results:
Urine Volume: 1.51 L
SS CaOx: 10.36
Urine Calcium: 259
Urine Oxalate: 41
Urine Citrate: 144
SS CaP: 3.24
24 Hour Urine pH: 6.431
SS Uric Acid: 0.37
Urine Uric Acid: 0.660
Na: 132
K: 43
Mg: 134
P: 1.061
Nh4: 41
Cl: 131
Sul: 37
UUN: 9.81
PCR 1.0
Cr 24: 1728
Cr 24/Kg: 23.8
Ca 24/Kg: 3.6
Ca 24/Cr 24: 150
I know I have to increase my fluids to at least 2.5 liters.What other changes would I need to make? The only high oxalate food I eat would be dark chocolate. Thank you so much for all your help. It is much appreciated.
Thanks again,
Mike
Hi Mike, sharp comment. Zonisamide inhibits carbonic anhydrase and raises urine pH and lowers urine citrate raising risk for kidney stones. Here is the FDA summary, kidney stones have their own section.I would not need to look further, and if possible your physicians should try to control your problem with an alternative class of medications. Regards, Fred Coe
Hi Dr Coe,
Thanks so much for providing this information about zonisamide. I”ll take it to my urologist and neurologist.
This has been so helpful.
Thanks again,
Mike
Here are the results of my most recent test:
Urine Volume: 1.79 L
SS CaOx: 8.91
Urine Calcium: 297
Urine Oxalate: 48
Urine Citrate: 221
SS CaP: 4.02
24 Hour Urine pH: 7.004
SS Uric Acid: 0.12
Urine Uric Acid: 924
Na: 267
K: 66
Mg: 137
P: 1149
Nh4: 36
Cl: 239
Sul: 49
UUN: 12.74
PCR 1.3
Cr 24: 2118
Cr 24/Kg: 29.5
Ca 24/Kg: 4.1
Ca 24/Cr 24: 140
Hi Mike, It looks as though you have high urine calcium and too low a urine volume. Your urine sodium – reflects intake – is very (very!) high at 267 mEq/d and I would try to lower it to 100 or less. That will lower urine calcium. If you do that and add water you might just do enough for prevention. But this is from an outsider. Your personal physicians are responsible. Best, Fred Coe
Thanks so much Dr Coe for all your help. I’m improving my water intake and will watch my sodium and will follow up with my neurologist and urologist
Thanks again,
Mike
Hi Dr. Coe, In March 2020, I am pretty sure I passed a large stone. Urinalysis just found gross hematuria (no UTI). My symptoms immediately resolved. The CT scan in August 2020 did not show any stones. I kept having symptoms to the point that I eliminated oxalates from my diet, drank citrus, and took magnesium (133mg/day once per day). This helped for a bit, but my symptoms seem to be getting worse especially if I don’t take magnesium. I’ve had a difficult time getting help. I have recently had cystoscope which was negative. I had a KUB which was also negative. The doctor says there is nothing more to do but I keep having symptoms. Here is my 24 hour urine results (stopped magnesium 3 days prior to starting test):
Cystine, Urine, Qualitative-neg
Urine Volume-3.17L
Calcium Oxalate Saturation-1.90 (low)
Calcium, urine- 90
Oxalate, urine-25
Citrate, urine-736
Calcium Phosphate Saturation-0.40
ph, 24 hour, urine 6.864 (high)
uric acid saturation-0.04
uric acid, urine-382
sodium, urine-62
potassium, urine-66
magnesium, urine-75
phosphorus, urine-399 (low)
ammonium, urine-18
Chloride, urine-68 (low)
Sulfate, urine-12 (low)
Urea Nitrogen, Urine- 4.23 (Low)
Protein Catabolic Rate 0.6 (low)
Creatinine, urine- 785
Creatinine/Kg Body Weight-11.2
Calcium/Kg Body Weight-114
I also had a metabolic panel. It was all within acceptable limits but calcium and chloride were at the upper limits of normal range. Calcium 10.2 (8.7-10.4 mg/dL) Chloride 107 (98-107 mmol/L)
Thank you very much!
Hi Kristy, You dilate very little on your symptoms so I have to guess they remind you of the stone you had years ago. If true that suggests passage of crystals. Like a stone, transient, rarely detected. But the urine results you post will not support the formation of crystals (very low SS values). This leaves me with either odd crystals (cystine, 2,8 hydroxyadenine) or odd periods of low urine flow in which crystals form that later on pass and cause symptoms. The high blood calcium points to possible primary hyperparathyroidism, which is a systemic disease – check out how to prove or disprove this disease).If you run to an ER during an attack they may be able to find the crystals in your urine. Of note the creatinine in the 24 hour urine is very low per kg body weight. Either you undercollected, have very low muscle mass, or have a high body fat content so the ratio of muscle to body weight is low. Regards, Fred Coe
Thank you Dr. Coe! I can’t thank you enough. This is so helpful in helping me put the pieces together. The symptoms I have are burning, frequency, change in flow until I drink, drink, have citrus, and drink more until the symptoms pass. Sometimes when I am not having symptoms, my urine flow starts out slow for some time and then suddenly increases. The big stone in 2020 looked like a big mass of blood and I did not know what was happening except I was in so much pain. The symptoms are milder than the big stone, but still pretty uncomfortable and ongoing. When I have symptoms, sometimes I see specs of blood. Now that I have the additional advice, all this leads me to believe it is crystals/clumps of crystals putting it all together. There are a couple of things important for my history. In 2020 when I passed the big stone, I was taking vitamin C and turmeric. I took those supplements for many years. I stopped seeing their risk with kidney stones, but keep having problems. I realize now the supplements were not wise, but when you have health problems, you do things you would not otherwise do. I have a history of giant cell tumor of the left pelvis (multiple surgeries, radiation 2000, recurrence and embolization in 2014, stable since that time-MD Anderson Center is wonderful). Due to my history, doctors assumed I had cancer with the blood in the urine. I knew it was not cancer based upon course and onset of symptoms and the fact that I was just seen for an MRI in Feb 2020 and the tumor was stable. Doctors kept looking at the elephant in the room and missed what I was voicing. One urologist referred me to oncology only for the oncologist, who I did not know I was referred to, tell me the KUB was negative. I’ve had to ask for the tests that have been done. I have seen more than one urologist who thought I had cancer. I agreed to the cystoscope thinking that they would then listen to my symptoms. After that was negative I was told to call back if I needed. I asked for a referral to nephrology because I feel something is wrong and I am not getting anywhere with urologists. I am told that my creatinine is normal and there is nothing wrong with my kidneys. The doctor made the referral but it’s been a couple of weeks now without a call from nephrology. I am having other symptoms that I do not feel are taken seriously. My hands turn purplish sometimes and I am pretty sure it is in relation to my diet. I’ve been watching my hands change colors since 2021. The last flare that I had my hands were purple-like and this time a little puffy. I had been eating alot of sodium that day. Still, I understand that I can’t be sure my hands are related to urinary symptoms until tests are done to rule out conditions. The doctor has also placed a referral to rheumatology, but it just took going to several doctors for this referral. I also noticed little white bumps on the joint of couple of my fingers when my hand is palm up. The X-ray showed soft tissue thickening. The urgent care doctor said it is not related. I’ve just had alot of changes with my hands along with the urinary symptoms. I am not sure they are related but need a work up with someone who takes my symptoms at face value instead of telling me that I am not experiencing what I am experiencing. I have just a couple of questions and I really appreciate your advice. This has been so helpful. 1)Is there a way that I can have tests done without having a flare to check for crystals (such as multiple urine tests to see if crystals show over time or blood work to show the condition specific to forming crystals; I have an upcoming appt with my PCP this week and will ask for parathyroid and also tests to rule out auto-immune disorders) 2) Can you recommend a doctor at either Duke or UNC Medical Center (or somewhere in NC) so I can get a referral from my PCP/switch my care to another doctor? If you can’t, that is ok. I just thought I would ask. I need a work up. I’m really having trouble getting a diagnosis and treatment. I really appreciate your time and expertise, and I cannot thank you enough. I’ve had symptoms for so long and I have hope that I can better advocate for myself with this information. Thanks!
Hi Kristy, If indeed crystals are causing your attacks them the causes of the crystals matter as one treats them. I think Duke or UNC would both work well for you. Both have excellent stone programs – on the web. I would choose for proximity. Either place can sort out the causes and find prevention for you. As for specific physicians, that is not so easy for me. IN general standards are very high in both places and the physicians know each other and have shared knowledge of the field. Regards, Fred Coe
I cannot thank you enough. Thank you very much for your time and expertise. It is appreciated.
Hi Kristy, Glad I could help you. Fred
Hi Dr. Coe,
Thank you so much for providing all this information and I am so grateful for your help!
I am a 5′ 5″, 65 year old woman weighing 120 lbs.
My results are as follows:
Total Urine Volume 2.39
PH Urine 6.8
Calcium 216
Oxalate 35
Uric Acid 810 Ref Range <700
Citric Acid 541
Sodium 93
Sulfate 11
Phosphorous 731
Magnesium 168
Ammonium 30
Potassium 95
Creatinine 809
Calcium Oxalate 1.34
Brushite 2.39 Reference Range <2.0
Sodium Urate 1.17
Struvite 5.65
Uric Acid 0.27
This patient has: Hyperuricosuria
Supersaturation Index with respect to Brushite (calcium Phosphate)
Suspected Problem is: Hyperuricosuric Nephrolithiasis
I'm not able to get in for an appointment for 2 months and questioning what changes I need to make at this time.
Thank you so much for your help!
Anne
:
Hi Ann, I know nothing about you but the single urine results – high pH, high brushite SS (needs to be below 1). A lot depends on what kind of stone you form (calcium oxalate or phosphate) how many and much more than that. Sans more, I can not add more. Best, Fred Coe
Hello Dr. Coe, There are some delays with speaking to my doc after a 2 day urine test so I thought I would post here for some additional insight. I have one stone, still in kidney, non obstructing, found via a CT for another issue. I am a 49yoF, no history of stones, no family history of stones. I did have a diet high in oxalates that I have since adjusted before testing:
Day 1
Cystine Urine – negative
Urine Volume – 2,180
Calcium Oxalate Sat – 3.23
Calcium Urine – 133
Oxalate Urine – 25
Citrate Urine – 341
Calcium Phosphate Sat – .45
ph – 5.958
Uric Acid Sat – .58
Uric Acid – 565
Sodium – 113
Potassium – 27
Magnesium – 102
Phosphorus – 810
Ammonium – 39
Chloride – 112
Sulfate – 33
Urea Nitrogen – 8.72
Protein Catabolic – 1.1
Creatinine 1,263
Creatinine/kg body weight (125lbs at 5 ft 7 in) – 22.3
Calcium/kg body weight – 2.3
Calcium/Creatinine Ratio – 105
2nd Day
Urine Volume – 2,850
Calcium Oxalate Sat – 2.58
Calcium, Urine – 119
Oxalate Urine – 29
Citrate Urine – 336
Calcium Phosphate Sat – .21
ph – 5.844
Uric Acid Sat – .61
Uric Acid Urine – 626
Sodium – 95
Potassium – 32
Magnesium – 94
Phosphorus – 778
Ammonium – 45
Chloride – 93
Sulfate – 40
Urea Nitrogen – 9.17
Protein Catabolic Rate – 1.2
Creatinine Urine – 1,229
Creatinine/kg body weight – 21.7
Calcium/kg body weight – 2.1
Calcium/Creatinine ratio – 97
Appreciate any insight. Thank you
Hi Jessica, The two urine samples seem consistent – urine creatinines match, and suggest you are rather fit (high creatinine/kg body weight). There is no stone risk except for low urine citrate on two occasions – for a woman. Your urine is more acid than among most women, which – along with the low citrate – raises a question about possible bowel alkali losses (laxatives, irritable bowel). Otherwise there is no stone risk. But you made a stone, meaning these data do not reflect your stone forming period, as you yourself pointed out. Regards, Fred Coe
Hello Dr Coe, I appreciate the response. Interesting on the urine acid notes. I do not use laxatives and have had some gastro analysis done which does not indicate irritable bowel issues. But who knows, I do have a fair amount of stress in my world, maybe that doesn’t help? I am working on increasing citrate (lemon water, more citrate fruits and will talk to the doc about supplementation). I believe I went overboard on oxalates. At one point I was eating a diet very high in them (almond everything, spinach, tofu, etc with almost no true dairy). I didn’t even know what an oxalate was until the stone was found. That combined with low citrate certainly created a breeding ground. Again, thank you for the guidance and here’s hoping this is my only! Also hoping it doesn’t grow or move, if it does surgery it is (lower pole of right kidney).
Hi Jessica, More fruits and veggies never cause any diseases I know of and may increase our citrate. Bests, Fred Coe
Hello Dr. Coe,
I am a 28 y/o male who has their first kidney stone a couple months ago. And was found to be 70% calcium phosphate. I had a 24 hour urine done and was wondering what your thoughts are!
Urine volume: 3510
Calcium oxalate Saturation: 3.67
Calcium: 435
Oxalate: 31
Citrate: 682
Calcium phosphate saturation: 2.40
Ph: 6.7
Uric acid saturation: 0.13
Uric acid urine: 1058
Sodium: 221
Potassium: 106
Magnesium: 153
Phosphorus: 1378
Ammonium: 46
Chloride: 217
Sulfate: 64
Urea nitrogen: 15.38
Just seeing what to make of these results.
Thanks!!
Hi Ryan, Very high urine calcium and high pH – the latter is not so common in young men and is why the stone is calcium phosphate. Is the CaP ‘apatite’ or ‘brushite’? The latter is far more concerning. One factor is your very high protein intake – raises urine calcium. Another is your high diet sodium (221 mEq/d) also raises urine calcium. One would generally start there. But if the stone is brushite one might want to do more right away. Regards, Fred Coe
I recently underwent a 24hr urinalysis. I had a 6mm stone which passed on its own. There are two smaller stones in me yet. I am low in the following fields:
Calcium oxalate saturation; 1.57
Oxalate,urine: 17mg
Citrate, urine: 447
Calcium phosphate saturation: .08
Ph 24 hr urine: 5.550
Phosphorous, Urine: 492
All other areas are within the normal range. May I have your thoughts? Much appreciated.
Hi Sherry, Your post is a tease: why are your saturations low? Is it high volume or low daily losses of calcium? Your urine is very acid, was your stone made of uric acid? Is the urine under-collected? No urine creatinine. So I cannot say much. Best, Fred Coe
Hello can you interpret this 24 hr litholink test please.
4190
High
2,64
Low
432
High
284
10/30/2023
28
28
10/30/2023
981
704 10/30/2023
Negative
Urine Volume (Preserved)o
Calcium Oxalate Saturation
Calcium, Urine0
Oxalate, Urine01
Citrate, Urine0
Calcium Phosphate
Saturation’
2.02
High
1.67
10/30/2023
pH,24hr, Urine0
7.043
High
6.867
10/30/2023
Uric Acid Saturation
0.08
0.13
10/30/2023
Uric Acid, Urine’
1547
High
1427
10/30/2023
Sodium, Urine01
93
56
10/30/2023
Potassium, Urine0i
141
High
140
10/30/2023
Magnesium, Urineo
236
High
104 10/30/2023
Phosphorus, Urine01
1072
1152
10/30/2023
Ammonium, Urine
52
44
10/30/2023
Chloride, Urine”
110
74
10/30/2023
Sulfate, Urine
83
High
72
10/30/2023
Urea Nitrogen, Urineo1
21.21
High
19.24
10/30/2023
Protein Catabolic Rateo1
2.3
High
2.1
10/30/2023
Creatinine, Urine”
1406
1073
10/30/2023
Note the excessive variation in creatinine excretion
suggesting a discrepancy in the collection process. The
urine creatinine result was verified by repeat analysis
Creatinine/Kg Body Weight”
22.5
High
16.g
10/30/2023
Calcium/Kg Body Weight
6.9
High
4.5
10/30/2023
Calcium/Creatinine Ratio0
307
High
264
10/30/2023
Commenta:
Note
Note
10/30/2023
Hi Jill, Indeed the two urine samples do not match, and the higher one seems over-collected. But a few things seem clear. Urine calcium is high, urine pH is high (alkaline urine) and your protein intake (PCR) is high both times – it should be 1 or so. Urine uric acid of 1400 mg/d is almost beyond imagining. I do not know the cause of all this but it would seem your diet is very high in protein and purines. Of course I know nothing about you except the bit you offer, so all causes are speculation. Even so, you seem to eat in an unusual way. Best, Fred Coe
Hi there! Thank you so much for your blog. It is incredibly educational and exactly what I’ve needed to interpret my labs. Would love your take on the following results and if there’s anything you recommend I do to prevent future stones. I am increasing citrate through lemon juice, drinking adequate water/day, and have increased my awareness of oxalate containing foods and how much I eat of them.
Stone:
33 mg stone
90% calcium oxalate monohydrate
10% calcium oxalate dihydrate
24 hr urine:
Creatinine 1400 mg/24 hr
Osmolality 24 hr urine 284 mOsm/kg
Ph urine 6.5
Calcium 81 mg/24 hr
Magnesium 78.2 mg/24 hr
Citric acid 469 mg/24 hr
Oxalic acid 16.6 mg/24 hr
Chloride 115 mmol/24 hr
Potassium 53 mmol/24 hr
Sodium 120 mmol/24 hr
Uric acid 483 mg/24 hr
Phosphate 598 mg/24 hr
Hi Jordan, The results amaze me given you say you form stones. Urine calcium is low, oxalate the same. You do not show supersaturations – vendors calculate them, and there is no urine volume. Even so osmolality is low – about that of blood – so SS cannot be high. So it would seem you cannot make stones. Either you do not or this sample does not represent you when you did. Best, Fred
Hi Dr Coe,
I had two stones surgically removed last December by the Cleveland Clinic (11mm and 13mm) one in each kidney and I have been told that I already have another 6mm stone. Unfortunately, the surgeon did not take a sample of the stone to see what type it is, so now they are trying to figure out how they were formed via these tests. I’m just not very confident thats the best approach, and frustrated they didn’t take a sample so we are spinning our wheels on this. Currently I’m attempting to live on a low oxalate diet, which is not too hard, but lots of conflicting information out there. Any chance you can see any trends in my last two tests?
First Test (2/19/24)
CYSTINE, URINE, QUALITATIVE – Neg
URINE VOLUME (PRESERVED) 3,160
CALCIUM OXALATE SATURATION 3.16
CALCIUM, URINE 307
OXALATE, URINE 28
CITRATE, URINE 709
CALCIUM PHOSPHATE SATURATION 1.87
PH, 24 HR, URINE 6.601
URIC ACID SATURATION 0.14
URIC ACID, URINE 768
SODIUM, URINE 284
POTASSIUM, URINE 55
MAGNESIUM, URINE 86
PHOSPHORUS, URINE 1,456
AMMONIUM, URINE 33
CHLORIDE, URINE 227
SULFATE, URINE 50
UREA NITROGEN, URINE 12.18
PROTEIN CATABOLIC RATE 1.4
CREATININE, URINE 2,247
CREATININE/KG BODY WEIGHT 35.4
CALCIUM/KG BODY WEIGHT 4.8
CALCIUM/CREATININE RATIO 137
Second Test (5/23/24)
URINE VOLUME (PRESERVED) 2,130
CALCIUM OXALATE SATURATION 6.94
CALCIUM, URINE 431
OXALATE, URINE 30
CITRATE, URINE 692
CALCIUM PHOSPHATE SATURATION 2.01
PH, 24 HR, URINE 5.998
URIC ACID SATURATION 0.77
URIC ACID, URINE 806
SODIUM, URINE 131
POTASSIUM, URINE 84
MAGNESIUM, URINE 143
PHOSPHORUS, URINE 1,321
AMMONIUM, URINE 36
CHLORIDE, URINE 147
SULFATE, URINE 48
UREA NITROGEN, URINE 12.88
PROTEIN CATABOLIC RATE 0.9
CREATININE, URINE 2,238
CREATININE/KG BODY WEIGHT 21
CALCIUM/KG BODY WEIGHT 4.0
CALCIUM/CREATININE RATIO 192
Hi Steve, Your situation seems dominated by very high urine calcium leading to a CaP SS of 1.8 and 2.1. Oxalate seems of minor concern. I would guess your stones contained a high percentage of calcium phosphate. As you report that a new stone formed rapidly I would hazard a far out guess – no better than that – you form brushite stones. Pity you have no analysis. NB the brushite article is still being edited, but will do for now. I would think your physicians would put forth a mighty effort to lower urine calcium as best they can. In saying all this, I am inferring a lot. The lack of stone analysis leaves us all a bit uncertain. But to lower urine calcium – that seems wise no matter what the stone were (except for the possibility of an odd composition). Regards, Fred Coe
Thank you for this helpful article! I am sharing my husband’s Litholink 24 Hr Urine Panel. Your thoughts are much appreciated.
Volume: 2,540 Normal
Calcium Oxalate Saturation: 3.14 L: 0.45ow
Urine 24 Hr calcium: 188 Normal
Oxalate 24 Hr: 32 Normal
Calcium Phosphate Saturation: 0.76 Normal
Uric Acid: 0.45 Normal
24 Hr Urine Sodium: 240 High
Urine 24 Hr Mg 120
Citrate 24 Hr Urine: 745
pH, 24 Hr Urine: 6.232 High
24 Hr Uric Acid: 904 High
Urine 24 Hr K: 104 High
24 Hr Ur Phosphorus: 1.036 Normal
Ammonium, Urine: 34 Normal
Sulfate, Urine: 44
Protein Catabolic Rate: 2.0 High
Creatinine/Kg Body Weight: 36.0 High
Calcium/Creatinine Ratio: 105 Normal
Urine 24 Hr Chloride: 271 High
24 Hr Urea Nitrogen: 14.29 High
Creatinine, 24 Hr Urine: 1,799
Calcium/Kg Body Weight: 3.8
Hi Elena, The urine creatinine is 1799 mg/24 hr, and also 36 mg/kg of body weight. This implies your husband is very small: creat per day/creat per day/kg bw = bw = 1799/39 = 49.9 kg. If he is not that small the urine is overcollected. Even so, there is little to find: calcium and oxalate are normal, SS CaOx is 3 and foe CaP 0.76. So it is not clear what caused his stones. Put another way this urine sample does not represent him when he did form stones. Best, Fred Coe