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.
Dr. Coe:
I received the below results and was wondering if you could interpret for me and offer an dietary recommendations?
Thank You very much.
Urine Volume- 1.75
SS CaOX- 10.87
Urine calcium- 338
Urine Oxalate- 43
Urine Citrate- 957
SS CaP
Hi Michele, I see the prior comment was incomplete. Your SS value is high because of low volume, and also high urine calcium and oxalate. The high urine calcium can arise from idiopathic hypercalciuria or other causes, the high oxalate often from low calcium diet. Regards, Fred Coe
Fred: Thank You for your comments.
If I have high urine calcium and high oxalate…how can I decrease my oxalate if I have to increase my calcium diet.
Does that make sense?
Thank You,
Michele
Hi Michele, It makes sense if you add in the other crucial part: Low diet sodium. This will lower urine calcium so you can eat calcium foods with meals apt to contain oxalate. That is the essential part of the kidney stone diet. Regards, Fred Coe
Hi Dr Coe,
I received the following results from my 24 hour urine test and was told I was a “stone former” ??. Can you take a look and perhaps help me understand what if any changes to my diet may help.
Calcium 339 mg
Oxalate 46 mg
Uric Acid 617 mg
Citrate 544 mg
pH 6.8
Total urine vol 1.62L
Sodium 131 mEq
Sulfate 19 mmol
Phosphorus 744 mg
Magnesium 148 mg
Ammonium 26 mEq
Potassium 69 mEq
Creatine 1131 mg
Calcium Oxalate 3.71
Brushite 5.85
Sodium Urate 2.54
Uric Acid 0.30
Thank you for your time
Suzanne
Hi Suzanne, Of course I do not know your clinical situation, not even the stone analysis, so my remarks are purely technical. Your urine volume is too low – needed is overl 2 liters/d, urine calcium is quite high, oxalate as well, and pH. People with urine like yours often form calcium phosphate stones – brushite or hydroxyapatite. Feel free to mention what I say to your physician, but it is your physician who is totally responsible for your care and who needs to decide what to do for stone prevention. Regards, Fred Coe
Hi. My daughter has been doing urine test once a week. Can you help me with results?
Leukocytes esterase ur 3 +
Calcium oxalate crystals 207 up
Urobilinogen .2mg
Hydaline cast 1.0
Thanks oh she is 7
Hi Lesley, I suspect she has genetic hypercalciuria and can be helped by low diet sodium and/or low dose thiazide diuretics. But she needs 24 hour urine testing to be sure. Hypercalciuria with crystals, and often hematuria, is well known in childhood. The white cell enzymes are, however, less common, and suggest inflammation, perhaps crystals, perhaps infection. Ask her physician if he/she thinks this is a reasonable idea, for her physician is in charge of her care. Regards, Fred Coe
I had 2 24-hour tests. One that was specific to kidney stone risk (which was 10 days ago and I don’t have the results from that one yet), and a regular 24-hour one which I got the results from this morning. Volume was 1.04L so I know I have to double my fluid intake. I had high Calcium oxalate (3.08), high sodium urate (2.44), low citric acid (249), low Mag (56), high brushite (5.87). Report says suspected problem: hypocitraturic nephrolithiasis. The one that I can’t figure out is the brushite and what that means. I’m already on a restricted diet: no gluten, dairy, soy, turmeric, chocolate, black tea, mango, tree nuts, peanuts, grapefruit because of allergies, my weight is normal (actually a little under), I’m 51, female. And I just started getting kidney stones Oct 2018. I’ve had 6 since then. My father has had about 20, and my older brother has had 4. I also have chronic UTIs (probably 150-200 in the last 20 years) and wondering if that has any effect on the stone formation.
Hi K Brown, A lot is missing here. What was in the urine? You are quoting only supersaturations. Brushite SS relates to calcium phosphate stones, and perhaps you make such stones but do not say what your stones are. Likewise low urine citrate is common with high urine pH, but you do not say. Here is a good place for you to try to put things together. See if it helps. Also, when stones begin later on in life there are special issues. Here is a good review of them. Regards, Fred Coe
Dr. Coe, I’m a 59 year old male and just recently discovered I had kidney stones. I had a large 1.8cm stone in one kidney and two smaller 3-4mm stones in the other. Had two lithotripsies to reduce the large stone. The stones were assessed as Calcium Oxalate between the lithotripsy sessions so I had made changes to my diet at that point. After the second lithotripsy and then having the stent removed I had my follow up. No new stone formation and we decided to do the 24 hour collection. My results came back and everything associated with Calcium stones was within the limits (calcium 124mg/day, oxalate 44mg/day, sodium 176 mEq, Calcium Oxalate SS .73). However, my Uric Acid was 774mg/day and Uric acid SS 1.59 and Brushite .28. Urine volume was 2.5L, PH 5.8, Phosphorous was high at 1145mg/day, Potassium 68 mEq/day, Ammonia 37 mEq/day, Creatinine 1850mg/day, Citric acid 637mg/day. The report suggested I have Hyperuricosuria. So while I’m pleased I have my Oxalate issue under control I’m a little perplexed about the uric acid issue. I’ve read your article on dealing with Uric acid stones but not quite sure specifically what I should do at this stage. Any insight and/or advice is appreciated.
Thank you,
Adrian
Hi Adrian, You have calcium oxalate stones, and your urine oxalate is quite high at 44 mg/d. Risk from urine oxalate begins at 25 mg/day. Uric acid stones are not present, and the borderline urine uric acid excretion is trivial. Common reasons for normal urine calcium and high urine oxalate include low diet calcium, as well as high diet oxalate. I would consider these possibilities. As well, conditions of your collection may not mirror those that caused your stones. Perhaps your life style or diet were quite different before now. Regards, Fred Coe
Dr. Coe thanks for your response. I did change my diet after the diagnosis of calcium oxalate stones but outside of the daily consumption of nuts, occasional spinach and potato it wasn’t that high in oxalates. I’ve upped diet calcium through dairy conisderably (1 cup of yogurt/cottage cheese & 2-4 oz of cheese daily plus vitamin supplement). I manage sodium intake as well. My fluids intake was always around 2-2.5 L but I’ve increased it to 3+ L. I’ll continue with tightly controlling the diet oxalates, consuming diet calcium and keeping the fluids up.
Hi Adrian, But be sure to check a new 24 hour urine to be sure about your stone risk. If you increased diet calcium without lowering diet sodium urine calcium might rise and increase stone risk. You do not mention lowering diet sodium – a crucial step. Regards, Fred Coe
Dr Coe,
Thank you for this website! I am a 59 year old male. 6’@ 148lbs, BP119/75, no meds yet. Passed first Kidney stone(Calcium Oxalate Dihydrate 20%, and Calcium Oxalate Monohydrate 80%), in October, 2019, 4mm from right kidney, still have 2mm and 1mm in left kidney. Ten days of agony so I am highly motivated to not repeat this experience. Urologist had me do one 24 hour urine eating and drinking as I had before passing the stone. When I was at the follow up appt. The doctor told me I had Hypocitraturia and low urine volume, in addition he said I eat too much animal protein and asked if I had ever been diagnosed with Gout. I didn’t see the actual numbers until I had found your web site and read your page on going over the results. The doctor prescribed 15mEQ Urocit-K 1 at breakfast,1 at dinner, plus produce >2L urine/day, eat less animal protein. The urine production part I am doing and cutting back on animal protein and realized I was eating ~3000mg sodium/day, now I have cut back there to ~2200/day, but I have had Irritable Bowel Syndrome most of my life and taking potassium citrate makes me feel sick all the time. I thought I could get used to it but haven’t been able too so far. I will try for a few days to a week and then need a week to feel better. I called about this and was told to stop and make an appointment. I have a follow up in March. Would going down to 5mEQ/day of the potassium citrate possibly let me get used to it? and my other questions: With my urine PH of 6.6 and supersaturation of brushite does it make sense to take the citrate? What in these numbers indicate Gout? In your page on Kidney stones and Middle Age, you list change in diet, well with IBS in the last 5 years or so I saw how much better I felt in eating a high protein low carb diet, but clearly it wasn’t good for my kidneys, so I have moved towards your recommended diet as best I can. For the acid load, are dairy products (cheese and yogurt) considered animal protein? Is there anything else you see in these numbers that I should bring up with my doctor at my next appointment? I will be requesting a second 24 hour sample since I really have changed my diet. Thank you, Norman
The results are below first for serum drawn the morning I dropped off 24hour sample, so I had not fasted (if that was important to the results)
Sodium 141
Postassium 3.8
Chloride 102
Carbon Dioxide 31
Creatinine 0.71
eGFR non-Afr American 102
Calcium 9.8
Magnesium 2.1
Phosphate (as Phosphorus) 2.4L ref. 2.5-4.5
Uric Acid 3.7L ref. 4.0-8.0
24 hour URINE Diagnostic—Urine Volume 1.55 liter low
PH Urine 6.6
Calcium 228mg/day
Oxalate 18mg/day
Uric Acid 501mg/day
Citric Acid 293L >320mg/day
Sodium 155mEQ/Day
Sulfate 20mmol/day
Phosphorus 682mg/day
Magnesium 98mg/day
Ammonium 40mg/day
Potassium 32 mEQ/day
Creatinine 1075 mg/day
Are these SS indexes-> Calcium Oxalate 1.30
Brushite 3.55H,
Sodium Urate 2.61H,
Struvite 5.67
Hi Norman, Your stone was 80% calcium oxalate monohydrate meaning a that calcium does not predominate greatly over oxalate. Your urine values are all normal except the oxalate is frankly so low I doubt the quality of the vendor who did the work. However the urine creatinine is also low for a mid life man, even one of very modest weight. Perhaps the urine is under collected. The ratio of urine calcium to urine creatinine – in grams – is very high, at 212, so I wonder if you have genetic hypercalciuria and an under collected urine that is deceiving us. That could also account for the faulty urine oxalate and low seeming urine citrate. I would do another urine, collect it fully, expect a lot more creatinine – about 1300 mg for your size if you are fit and not fat. That will clarify matters. As for potassium citrate, you probably have normal urine citrate with a full collection. Regards, Fred Coe
My us came back saying calcium oxalate crystals. Rare abnormal. What does that mean?
Hi T, I do not know what us means. If it means ultrasound, then you may well have stones in your kidneys. If it means urinalysis and crystals were seen under the microscope then you may have some urine abnormalities that predispose to stones. In either cause you may want to be evaluated for possible causes of stones so prevention can be undertaken. Regards, Fred Coe
Dr. Coe, My son is 12 years old, and a random sample ( not collected sample) of urine was analyzed. The results were as follows:
1- Urine Oxalate ( Colorimetric) = 0.86 (without reference rang)
2- Urine Citrate = 0.42 mmol/L (without reference rang)
3- Uric Acid – urine = 1088 (reference range: 446 – 2944)
4- Urine Calcium =1.68 (reference range: 0.5 – 4.37 )
5- Urine Creatinine = 3470 (reference range: 5300 – 22100 )
in addition to, other blood analysis as follows:
1- CA – Calcium = 2.35 (reference range: 2.12 – 2.52 )
2- CREA – Creatinine =47 (reference range: 53 – 115 )
could you please evaluate the results
Is there a deficiency in Urine Citrate level?
Thanks
Regards
Hi Ali, I am afraid these measurements are not interpretable by me. You need the full 24 hour day so one can compare to normal children. Likewise, you do not give units. Is the creatinine in mg/l, mmol/l, or are these total amounts in the collection. Regards, Fred Coe
thanks for your cooperation, creatinine in µmmol/l
how can calculate the urine citrate/creatinine ratio mmol/mmol
Hi Ali, I suggested you might like to send along all the measurements with units and I can try to help. Fred
Updated, new analysis for random urine creatinine is 100 mg/dL
Hi Ali, But all the other units? Can you repost with all the tests showing their units? Fred
Dr Cole,
I’m about to go and get my second cluster of stones lasered in a few weeks time. This will be the second time on 6 months. The only irregular findings in my 24hr urine testing was that my Oxalate levels were high. I understand that I have change my diet to consumer fewer oxalates, and also increase my calcium intake with meals. I have spoken to my specialist, and GP re some severe tiredness that I’ve been experiencing (also experienced this leading up to the kidney stones being lasered in the past), both my GP and urologist seems to think that the tiredness and kidney stones are not linked.
However my GP has noted that I have a Vitamin D deficiency, and has prescribed some Vitamin D supplements. However, I am under the impression that Vitamin D supplements can increase the risk of kidney stones! Clearly I do not need a higher risk of stones. Any ideas?
Hi Stuart, Be sure about how high the oxalate is – it should be well below 80 mg/d. Vitamin D deficiency needs treatment, and such treatment should not raise urine calcium unduly. But sometimes vitamin D deficiency masks idiopathic hypercalciuria or even primary hyperparathyroidism, so be sure and check blood and 24 hour urine when your D levels are normal. Regards, Fred Coe
Hello, Dr. Coe, I’m posting my results below and was curious on what they mean.
Urine Volume 3.16
SS CaOx 2.61
(liters/day)
Urine Calcium (mg/day) 118
Urine Oxalate (mg/day) 35
Urine Citrate (mg/day) 552
24 Hour Urine pH 6.141
SS CaP .29
SS Uric Acid .31
Urine Uric Acid (g/day) .611
Can you please tell me what it means?
Hi Vince, Strictly by numbers stone risk is very low. In fact you have no obvious abnormal results. But lab results need a context. So what I say is just that – the numbers are not pointing to anything abnormal. Best, Fred Coe
Hi Dr. Coe,
I was poisoned by multiple heavy metals by unknowingly drinking a health product that was contaminated with toxins in Nov 2018. I was 37 and healthy. I noticed crystals in my urine ever since the incident. All shapes, sizes, colors that I can see with my naked eye. I had labs done March 2020 by the Mayo Clinic. This 1 yr and months later since I drank toxins. Can you please help interpret them. They are a 24 hr urine.
Calcium oxalate 1.36DG
Brushite 0.22DG
Hydroxyapatite 5.55DG
Uric acid is -2.66DG
Sodium Urate 2.65DG
Sodium, random U 152mmol/L
Calcium random 5mg/dL
Calcium/creatinine ratio 0.02mg/mg
Magnesium random 20mg/dL
Magnesium/Creatinine ratio 0.094mg/mg
Potassium random 59mmol/L
Chloride random 91mmol/L
Phosphorus pediatric random 77mg/dL
Phosphorus/Creatinine ratio 0.36mg/mg
Sulfate random 229.9mg/dL
Citrate excretion 35.9mg/dL
Citrate/creatinine ratio 0.17mg/mg
Oxalate pediatric random 0.59mmol/L
Oxalate concentrations 51.93mg/L
Oxalate/creatinine ratio 0.02mg/mg
pH random 6.8
Uric acid random 51mg/dL
Uric acid/creatinine ratio 0.24mg/mg
Creatine random 212mg/dL
Osmolality random 906mOsm/kg
Ammonium random 25mmol/L
Thank you kindly for your help!
Jessica
Hi Jessica, I cannot do it properly. You need to multiply the concentrations by the liters/day of urine which will given the amounts of material lost in the urine daily. These are all concentrations. The only measurement I can interpret well is your urine calcium which is given in mg/mg of urine creatinine. Usual values for urine calcium are per gm of creatinine so your value is 20 mg/gm creatinine, a low number. This could arise from many reasons – low calcium diet, vitamin D deficiency, reduced kidney function. Without serum values I cannot know the latter. Moreover, you should gather some of the urine crystals and get them analysed – what they are made of may be important. Regards, Fred Coe
Hello Dr. Coe,
I am a 47 yr old female and I just had my first stone. It was 12 mm and therefore I had emergency surgery and the stone was lasered. Unfortunately, I wasn’t able to pass anything large enough to analyze after the surgery. I recovered and just did my 24 hr urine risk profile and got the results. i was told I am an unusual case with Excellent volume (I’ve been drinking 90 oz of water daily since i got the stone on April 15th and i only weigh 117 lbs. but i was hoping it would help me as i knew that hydration can cause stones), Borderline low citrate, Low to normal calcium but very high oxalate. I fear that I caused this to occur because I went on a lectin free diet and was taking in very little calcium and was salting a lot of veggies, but mostly eating millet, spinach, dark chocolate, nuts and sweet potatoes on an almost daily basis as i had no idea anything about oxalates or kidney stone risk from diet until this happened to me. My hydration level was not this great in the past and i am wondering if my sodium level would have been much higher had i taken the test when i was only drinking about 40 oz of water daily? Can a person decrease their sodium levels by drinking more water daily? in looking at my numbers, do you think i need to cut salt or just increase calcium or should i also consider taking calcium citrate? Should i drink lemon juice for the citrate? i am hesitant to take calcium citrate since i read through your site and it seems like trying to cut sodium and increase calcium as well as limit oxalate intake might help bring my levels back to normal, but i wanted your opinion on these results if you could please share it. Thank you for all the great articles and for responding to so many comments!
Total Volume, Ur 3300 mL/24 hr
Total Volume: 3300 mL
Preserved Urine Volume 3300 mL/24 hr
Ammonia, Urine 13630 ug/dL
Ammonia, 24HR Ur 26 mEq/24 hr
Calcium, Ur 3.4 mg/dL
Calcium 24HR Ur 112.2 mg/24 hr
Citrate, Ur 98 mg/L
Citrate 24H UR 323 mg/24 hr
Chloride, Ur 36 mmol/L
Chloride 24HR Ur 119 mmol/24 hr
Creatinine, Ur 21.6 mg/dL
Creatinine,Ur 24hr 712.8 mg/24 hr
Cystine, Quan. Urine 1.42 mg/L
Cystine, Quant, Ur, 24hr 4.69 mg/24 hr
Magnesium, Ur 1.6 mg/dL
Magnesium, 24H Ur 53 mg/24 hr
Oxalate, Ur 22 mg/L
Oxalate, 24HR Ur 73 mg/24 hr
Osmolality, Ur 180 mOsmol/kg
pH, 24 Hr Urine 6.1
Phosphorus, Ur 14.2 mg/dL
Phosphorus, 24HR Ur 468.6 mg/24 hr
Potassium, Ur 15.9 mmol/L Not Estab. mmol/L
Potassium, 24HR Ur 52.5 mmol/24 hr
Sodium, Ur 30 mmol/L
Sodium, 24HR Ur 99 mmol/24 hr
Sulfate, Ur, mEq/L 5 mEq/L
Sulfate, 24H Ur 17 mEq/24 hr
Uric Acid, Ur 8.6 mg/dL
Uric Acid, 24HR Ur 284 mg/24 hr
Brushite 0.19 ratio
Calcium Oxalate 4.53 ratio
Monosodium Urate 0.28 ratio
Struvite 0.01 ratio
Uric Acid 0.29 ratio
Hi Nicole, I believe you wrote about delayed testing. The urine seems under collected given the creatinine of 712 mg/d. This is common when volume is so high – the container fills up. Urine calcium is not low but actually a bit high: calcium is 3.4 and creatinine 21.6 (mg/dl for both) with a ratio of 157 mg calcium/gm creatinine – upper limit is about 140. Oxalate is simply immense at 73 mg/d and surely is from the low calcium high oxalate diet. But given a substantial urine calcium despite such a diet I suspect that with a normal calcium intake your urine calcium will rise significantly. Urine sodium is 99 mmol/d and the urine is not fully collected, so you have some room to lower sodium intake to control your urine calcium. Your prior note mentions this strategy. At 323 mg/d citrate is a bit low but with a full collection it may not be really low. As for the urine volume you have raised it, as you noted, and lowered stone risk. Urine sodium is diet sodium intake, on average, and independent of water intake. I presume you are not eating 1000 mg of calcium, and massively reduced your diet oxalate, and your next 24 hour urine will be very different. I think you have idiopathic hypercalciuria so urine calcium may be quite high – this is managable. By all means recheck soon! Regards, Fred Coe
Hello Dr. Coe,
I am a 47 yr old female and I just had my first stone. It was 12 mm and therefore I had emergency surgery and the stone was lasered. Unfortunately, I wasn’t able to pass anything large enough to analyze after the surgery. I recovered and just did my 24 hr urine risk profile and got the results. i’ve been drinking 90 oz of water daily since i got the stone on April 15th and i only weigh 117 lbs. but i was hoping it would help me as i knew that hydration can cause stones). I fear that I caused this to occur because I went on a lectin free diet and was taking in very little calcium and was salting a lot of veggies, but mostly eating millet, spinach, dark chocolate, nuts and sweet potatoes on an almost daily basis as i had no idea anything about oxalates or kidney stone risk from diet until this happened to me. My hydration level was not this great in the past and i am wondering if my sodium level would have been much higher had i taken the test when i was only drinking about 40 oz of water daily? Can a person decrease their sodium levels by drinking more water daily? in looking at my numbers, do you think i need to cut salt or just increase calcium or should i also consider taking calcium citrate? Should i drink lemon juice for the citrate? Thank you for all the great articles and for responding to so many comments!
Total Volume, Ur 3300 mL/24 hr
Total Volume: 3300 mL
Preserved Urine Volume 3300 mL/24 hr
Ammonia, Urine 13630 ug/dL
Ammonia, 24HR Ur 26 mEq/24 hr
Calcium, Ur 3.4 mg/dL
Calcium 24HR Ur 112.2 mg/24 hr
Citrate, Ur 98 mg/L
Citrate 24H UR 323 mg/24 hr
Chloride, Ur 36 mmol/L
Chloride 24HR Ur 119 mmol/24 hr
Creatinine, Ur 21.6 mg/dL
Creatinine,Ur 24hr 712.8 mg/24 hr
Cystine, Quan. Urine 1.42 mg/L
Cystine, Quant, Ur, 24hr 4.69 mg/24 hr
Magnesium, Ur 1.6 mg/dL
Magnesium, 24H Ur 53 mg/24 hr
Oxalate, Ur 22 mg/L
Oxalate, 24HR Ur 73 mg/24 hr
Osmolality, Ur 180 mOsmol/kg
pH, 24 Hr Urine 6.1
Phosphorus, Ur 14.2 mg/dL
Phosphorus, 24HR Ur 468.6 mg/24 hr
Potassium, Ur 15.9 mmol/L Not Estab. mmol/L
Potassium, 24HR Ur 52.5 mmol/24 hr
Sodium, Ur 30 mmol/L
Sodium, 24HR Ur 99 mmol/24 hr
Sulfate, Ur, mEq/L 5 mEq/L
Sulfate, 24H Ur 17 mEq/24 hr
Uric Acid, Ur 8.6 mg/dL
Uric Acid, 24HR Ur 284 mg/24 hr
Brushite 0.19 ratio
Calcium Oxalate 4.53 ratio
Monosodium Urate 0.28 ratio
Struvite 0.01 ratio
Uric Acid 0.29 ratio
I believe this is a duplicate that I have already answered. Fred
HI Dr,
I’m 36 years old Male, recently procedure has been performed to remove kidney stones. My urologist order for 24hr urine sample to identify root cause for kidney stones formation and below is the report. Could you please provide your analysis?
Stone Risk Factors
Vol 24 – 4.41
SS CaOx – 0.29
Ca 24 – 15
Ox 24 – 39
Cit 24 – 431
SS CaP – 0.02
pH – 6.342
SS UA – 0.10
UA 24 – 0.429
Dietary Factors
Na 24 – 180
K 24 – 59
Mg 24 – 91
P 24 – 0.411
Nh4 24 – 32
CI 24 – 221
Sul 24 < 13
UUN 24 – 5.11
PCR – 0.8
Hi Vinayaka, Frankly, I am surprised you have a stone. Urine calcium of 15 mg/d – if the units are that – is pathologically low. Your SS values for CaOx and CaP are below solubility. Perhaps your urine volume was very, very much lower when you formed the stone – whose composition you do not mention. Regards, Fred Coe
Dear Dr Coe,
I’ve been having abdominal pain for several months. An AB CT Scan showed a tiny stone. Here are the results of my 24 hr urine test.. Could the AB pain be caused by this? How would you handle my case? Meds? Diet? Testing?
Component Results
Component Your Value Standard Range Flag
TOTAL URINE VOLUME 2.42 L/day >2.00 L/day
See Note 1
PH URINE 6.6 5.5 – 7.0
Calcium, Ur 367 mg/day <250.0 mg/day H
See Note 1
Oxalate Urine 28 mg/day <45 mg/day
See Note 1
URIC ACID URINE 743 mg/day 320 mg/day
See Note 1
Sodium, Ur 182 mEq/day <200 mEq/day
See Note 1
Sulfate, Ur 18 mmol/day <30 mmol/day
See Note 1
Phosphorus, Ur 1,254 mg/day 60.0 mg/day
See Note 1
POTASSIUM URINE 57 mEq/day 19 – 135 mEq/day
See Note 1
Creatinine Urine 1,818 mg/day 800 – 2,000 mg/day
See Note 1
CALCIUM OXALATE 1.34 <2.00
BRUSHITE 3.95 <2.00 H
SODIUM URATE 1.95 <2.00
URIC ACID 0.38 <2.00
The Patient Has:
Hypercalciuria
Hyperuricosuria
Supersaturation Index w/ Respect To:
Brushite (Ca phosphate)
Suspected Problem is:
Hypercalciuric Nephrolithiasis
Hyperuricosuric Nephrolithiasis
Note 1
This test was developed and its analytical performance
characteristics have been determined by Quest
Diagnostics. It has not been cleared or approved by the
FDA. This assay has been validated pursuant to the CLIA
regulations and is used for clinical purposes.
COMMENTS CANCELED
Result canceled by the ancillary.
Hi Jon, You have a single stone not obstructing and pain that does not seem due to the stone. Your 24 hr urine shows high calcium excretion possibly due to genetic hypercalciuria, and a rather high diet sodium intake that would raise urine calcium. But this is not a sufficient evaluation; here is a good outline of what you need. Get fully studied. If it is genetic hypercalciuria, reversal and treatment is reasonably straightforward – here is a good link to that. Regards, Fred Coe
Dr. Coe: Re: 24 hr. stone risk test. My son is 51yrs. old. Has ability of 4mth. old. Cannot tell him when to urinate since he does not understand. Collect the urine using a condom catheter. I think the lab requires a 2 ltr. collection during 24 hrs. in order to achieve an accurate test result, (1) If only one liter is collected during 24 hr. period would this invalidate the results? (2) If I continue collection for 30 hrs. in order to achieve 2 ltr. collection would this also make the results not valid?
Thank you, Joe G.
Hi Joe, the volume of urine is not the issue it is that a complete 24 hour collection is obtained. A condom catheter should be adequate to obtain a full day of urine. The lab can use any volume collected during a 24 hour period provided it is indeed a full day’s collection. Regards, Fred Coe
My urine saturation profile test results are:
Uric Acid: 417 mg/day
Oxalate: 51.8 mg/day
Calcium: 363 mg/day
Citrate: 780 mg/day
Sodium: 153nmol/day
Phosphorus: 1014mg/day
Magnesium: 81 mg/day
Calcium Oxalate: 7.765
Calcium Phosphate: 4.985
Urine Volume: 3 litre
what does it mean?
Hi Govind, Technically your urine calcium is high and oxalate, too. You have significant risk for calcium phosphate and oxalate stones. Lacking clinical information, I cannot say more. Your physician needs to treat these problems to prevent stones. Regards, Fred Coe
Hello! I’m a 50yo female. I had surgery in May to remove 6mm stone. First surgery but fourth stone (started getting stones in my early 30s). My results came back as follows for a 24 hour collection on 6/5/20. I have been doing keto for three weeks now (beg 6/27/20) and would like to know based on my lab results if I’m increasing or decreasing chances of another stone from this diet. I’m really trying to avoid taking medication to prevent stones. I drink a ton of water and always have and sometimes wonder if the filtered water could be contributing to stones or possibly genetic, since I’ve had calcification of my right ovary since 20s which is same side as kidney stones. Any feedback is appreciated.
Stone Risk Factors/Cystine Screening: Negative (6/8/20)-
Vol: 2.38
SS CaOx: 5.34
Ca: 361
Ox: 22
Cit: 710
SS Cap: 1.90
pH: 6.372
SS UA: 0.21
UA: 0.513
Dietary Factors-
Na: 105
K: 39
Mg: 89
P: 0.733
Nh4: 31
CI: 102
Sul: 26
UUN: 8.36
PCR: 0.9
Normalized Values-
Weight: 69.0
Cr 24: 1190
Cr 24/Kg: 17.3
Ca 24/Kh: 5.2
Ca 24/Cr 24: 303
Thank you!
Hi GinaB, OF course I do not know your medical history so my comments are purely technical and not medical advice. Your urine calcium is very high and that is a well known cause of calcium stones. As this urine was taken before the keto diet I have no idea what the diet might do. Here is a good article to help orient you as to what to do. The high urine calcium can have a number of causes – here is a good review. The common reason is genetic hypercalciuria, which you probably have.I hope this helps. What you most need is a skilled physician who understands stone prevention, and I hope you have such available. Regards, Fred Coe
I had my first stone crushed in March 2020. I donated blood on July 24th and then had to have bloodwork done for my annual physical. My GFR was at 51 with creatinine at 1.2. Last November they were at 85 and .7. Could the whole blood donation have affected these numbers or should I assume the stone caused damage or is reforming?
The blood draw was 3 1/2 weeks after the whole blood donation.
Hi Kathleen, Blood donation has no role, but shock wave lithotripsy or ureteroscopy can indeed lower kidney function. A big concern is whether fragments from your March procedure have obstructed the kidney, and perhaps your physician might want to be sure about that. I am suspicious. Regards, Fred Coe
Recently had urine test and I am a stone suffer, The following areas where slightly elevated
Monosodium Urate reading from Labcorp was 4.71 (high)
Sulfate, Urine reading was 33 (high)
and critic acid was 145 (low)
currently on indapamide 1.25mg
what does this mean? what do i have to do to maintain normal levels again?
Hi Ernie, From so limited an amount of information I an afraid I cannot be of help. The sulfate is simply from diet protein intake. The low urine citrate may be from indapamide, which depletes the body of potassium, and that in turn lowers urine citrate. Your physician has access to all of your information going back in time, and you need she/he to figure out if your treatment is or is not sufficient to prevent more stones. Regards, Fred Coe
Hi Dr. Coe,
Should I be concerned about the following analysis from the 24hr? I’m approx 4’11 & under 100lbs (about 95) so was always informed a size weight ratio is different for all when these results are provided but I’m also not a Dr. All labs were in range except the following below. I have been suffering for almost a year. My medical situation is unique being thyroid cancer took me into a constant state of being in suppression & having a colon resection. So I know my body doesn’t absorb all nutrients but this isn’t new for me. It’s been over 10yrs & never have I passed more stones back to back than now. It was always once in a 5yr blue moon.
Alkaline PH 7.6
Output: 1.78
Uric Acid: 486
Brushite: 4.56
Struvite: 118.41
Any insight would be so greatly appreciated.
Kindest regards,
Blair Bodrato
Hi Blair, You do not mention the type of stones, but you do mention colon resection. The urine has a very high pH, whereas pH is usually low with less colon, so I wonder about infection. Are your stones calcium phosphate, struvite? Is urine ammonia low or high? If you give me more information I could try to offer better suggestions. Regards, Fred Coe
Hello Dr. Coe, I was to see you soon but your appointments have just been pushed back. I was hoping you may answer here if I can do things to help myself feel better sooner. I’m supposing calcium and/or magnesium citrate could help but I’ve tried various supplements over the last 9 months and have just you’d so I am anxious. I am in so much discomfort and pain, mostly in my body vs kidney’s, ie; joints, muscles, inflammation and disrupted sleep, so I am wanting to lay down most of the time. My pain Dr. Doesn’t understand how bad I feel and is pushing me as to why I am bedridden and not going to physical therapy.
I was on miralax over 10 years and have suffered greatly but I am gracious to God that he allowed wisdom to point me in the right direction. I am about 9 months post discontinuation of miralax and also a low oxalate diet.
My results that stick out are:
Ss caox 14.40
Ph urine 6.78
SS Cap 1.91
Yes, my urine output is low, I will try to drink more, I dont know why I cant.
Dietary factors
Pcr 0.6
Blood
Phosphorus 4.6
Co2 32, I was diagnosed as cough variant asthma, I deduced that this is oxalate related since burning of plant matter, wood, triggers the persistent cough for almost a week and from input from oxalate/autism researcher, Susan Owens and support group for oxalate sufferers.
Thank you greatly, Christine
Hi Christine, I am sorry about the wait – Of all you have said, with respect to any urinary symptoms the most important matter is your urine volume. Otherwise, we should wait until I can visit with you and review all of your details. Regards, Fred Coe
Hello Dr. ,
My name is Maria. From last two months I m having severe back pain+ front and Hip area pain, vomit, fever, incomplete urination + frequent, sleepless. Recently I have blood test which shows epithelial cells, protein trace, CA oxalatr crystal, blood, pus cell2-4,red blood cells.
Urine appearance is yellow, PH 5, turbid, 30ml , specific gravity is quite high.
Leukocyte count is high, platelet count is at lower side.
X-ray is clear
Kindly suggest me what to do.
Hi Maria, It seems likely you have urinary infection, at least as a possibility, and your physicians need to evaluate it. The crystals can form in a highly concentrated urine, as this one was – high specific gravity. Much higher fluid intake should make an end of the crystals, and since your x ray is negative and you have no stone passage history I would not think more needs be done about stones. However if there is no stone, and if your urine continues to show blood or white cells, a CT scan would be more definitive for stones or other causes. Of course, this is mere outsider suggestions, your personal physicians are responsible for your care and may think otherwise, for good reasons. Regards, Fred Coe
Hi Dr. Coe,
I just had a urine test done. My first test 6 months ago and this test varied widely with regards to phosphorous and sulfate. I don’t eat tons of meat, but I greatly increased calcium intake to offset high oxalates in my test 6 months ago so that may be the result of more protein intake. Should I be concerned?
Phosphorus, 24 HR ur went from 468.6 to 1779.7
Sulfate, 24 HR ur went from 17 to 56
Calcium went from 112 to 344
Oxalates fell from 73 to 19
Citrate still low from 97 to 98
Full results:
Total Volume, Ur 3700 mL/24 hr
Total Volume: 3700 mL
Preserved Urine Volume 3700 mL/24 hr
Ammonia, Urine 33360 ug/dL
Ammonia, 24HR Ur 72 mEq/24 hr
Calcium, Ur 9.3 mg/dL
Calcium 24HR Ur 344.1 mg/24 hr
Citrate, Ur 97 mg/L
Citrate 24H UR 359 mg/24 hr
Chloride, Ur 25 mmol/L
Chloride 24HR Ur 93 mmol/24 hr
Creatinine, Ur 29.7 mg/dL
Creatinine,Ur 24hr 1098.9 mg/24 hr
Cystine, Quan. Urine 6.41 mg/L
Cystine, Quant, Ur, 24hr 23.72 mg/24 hr
Magnesium, Ur 3.9 mg/dL
Magnesium, 24H Ur 144 mg/24 hr
Oxalate, Ur 5 mg/L
Oxalate, 24HR Ur 19 mg/24 hr
Osmolality, Ur 324 mOsmol/kg
pH, 24 Hr Urine 5.3
Phosphorus, Ur 48.1 mg/dL
Phosphorus, 24HR Ur 1779.7 mg/24 hr
Potassium, Ur 18.4 mmol/L
Potassium, 24HR Ur 68.1 mmol/24 hr
Sodium, Ur 26 mmol/L
Sodium, 24HR Ur 96 mmol/24 hr
Sulfate, Ur, mEq/L 15 mEq/L
Sulfate, 24H Ur 56 mEq/24 hr
Uric Acid, Ur 9.2 mg/dL
Uric Acid, 24HR Ur 340 mg/24 hr
Brushite 0.31 ratio
Calcium Oxalate 1.92 ratio
Monosodium Urate 0.14 ratio
Struvite 0.01 ratio
Uric Acid 1.10 ratio
Thank you for looking at this!
-Nicole
Hi Nicole, You increased your protein load about double. This raised your urine calcium, sulfate, ammonia, and lowered pH, and no doubt your increased diet calcium raised your urine calcium as well. Because oxalate fell so low SS CaOx is trivial and because the pH is so low CaP SS is very low. Perhaps you may have overdone things just a bit on the protein intake – I do not see a PCR value but it should be there and should be around 1.0. Urine phosphate is simply from diet, and more protein and milk more phosphate – it is not a stone risk. Of course, I do not know your medical situation, so these comments are for you AND your physician, who is in charge. Regards, Fred Coe
Hi Dr. Coe,
After seeing your website I was very interested as well as the professionalism you show by responding. I know this is not for medical advice (but it would be nice to see another opinion) I’ll give a little background: first stone attack at 12 & hospitalized, lithrotripsy at 18, in and out of urgent care due to frequent UTIs and stone attacks. I have about 6 UTIs a year. I have bilateral stones. I have uteroscopy scheduled for the removal of the seven stones currently residing in my left and right kidneys next year. I am currently seeing multiple doctors to figure out if it is a genetic condition. I have been struggling with this for 13 years now! (I’m a 25 yr old female)
Here is my most recent 24 HR test
24 hr Uric Acid .547 g/d
Urine pH: 6.415
24 hr Oxlate: 16 mg/d
24 hr Citrate: 242 mg/d
24 hr Calcium: 217 mg/d
Urine Volume 1.64 L/d
Supersaturation CaOx: 4.31
Supersaturation CaP: 2.44
24 HR Creatinine: 1,290 mg/d
Creatinine per body weight kg: 17.9 mg/d/kg
24 hr Calcium per Kilogram Body Weight 3.0 mg/d/kg
24 hr Calcium per 24 hr Creatinine 168 mg/g
24 hr Sulfate 23 mEq/d
24 hr Chloride: 74 mmol/d
24 hr Ammonium 27 mmol/d
24 hr Potassium 31 mmol/d
24 hr Sodium 85 mmol/d
24 hr Phosphorus 0.837 g/d
24 hr Urea Nitrogen 7.54 g/d
24 hr Magnesium 82 mg/d
Protein Catabolic Rate 0.8 g/kg/d
Hi Claire M, Your urine is like that of a calcium phosphate stone former, with its high CaP SS and ammonia excretion exceeding sulfate. Your urine calcium is a bit high, volume low. It is the low citrate that makes your physicians concerned about genes, and I suspect it is indeed inherited, but that is nothing much for clinical practice. Frankly to me you seem rather routine. I do note the low urine potassium, making me wonder about prior diuretics, or acid blockers, or diet issues. Of course this is not a medical opinion, as I do not even know your stone type – by now it might be struvite, with all the infections, or brushite – a special kind of problem. Regards, Fred Coe
Dr. Coe:
I recently had a LithoLink 48 hour study done with the following (partial) results:
Calcium Oxalate 27, 26
Volume 2240, 2100
Calcium Oxalate Saturation 3.34, 3.61
The ranking scale that my health system portal attached to that last result ranking it as “low”, but elsewhere you have written that a saturation above 1 is high and a risk factor. Is Litholink calculating this saturation in a different way than you do, or is the health system ranking incorrect in your judgment?
Hi Michael M, I think ‘Calcium Oxalate’ looks like 24 hour oxalate, and is normal. The SS values for CaOx are not very high. The one that needs to be below 1 is for calcium phosphate (CaP). The Litholink analysis was written by me when I owned the company, and I have no idea how a health system could possible make up its own scales. I hope this does answer your question but you do not post the CaP SS so I cannot be sure. Regards, Fred
Hi
My ct scan kidney stone report shows 10×8 ×7 (ap×cc×tr) with average denisity of renal calclus how much this is in mm? Like 7 8 or 9mm?
Hi Manpreet, most radiologists use mm as their unit, so the stone ranges from 7 to 10 mm. Fred
Hi dr
My kidney ct scan report shows i have kidney stone measuring 10 × 8 ×7 (ap×cc×tr) with average hu 1700. How much this is in mm like 5 6 or 7 mm or greater than that? Thanks
Should I be concerned with the high levels present?
-Cystine, Urine, Qualitative: neg
(normal)
-Urine Volume (Preserved): 1400ml/hr
(normal)
-Calcium Oxalate Saturation: 7.94
Range 6-10
(normal)
-Calcium, Urine: 179 mg/24
(normal)
-Oxalate, Urine: 34 mg/24hr
(normal)
-Citrate, Urine: 773 mg/24hr
(normal)
-Calcium Phosphate Saturation: 2.3
Range 0.5-2
***(HIGH)
-pH, 24 hr, Urine: 6.482
Range 5.8-6.2
***(HIGH)
-Uric Acid Saturation: 0.29
Range: <1.00
(normal)
-Uric Acid, Urine: 547 mg/24hr
(normal)
-Sodium, Urine: 123 mmol/24hr
(normal)
-Potassium, Urine: 67 mmol/24hr
(normal)
-Magnesium, Urine: 79mg/24hr
(normal)
-Phosphorus, Urine: 869 mg/24hr
(normal)
-Ammonium, Urine: 36 mmol/24hr
(normal)
-Chloride, Urine: 119 mmol/24hr
(normal)
-Sulfate, Urine:32 meq/24hr
(normal)
-Urea Nitrogen, Urine: 7.91g/24hr
(normal)
-Protein Catabolic Rate: 1.3 g/kg/24hr
(normal)
-Creatinine, Urine: 1523 mg/24hr
(no ref range)
-Creatinine/Kg Body Weight: 33.6 mg/24hr/kg
***(HIGH)
-Calcium/Kg Body Weight: 3.9 mg/24h/kg
(normal)
-Calcium/Creatinine Ratio:117 mg/g creat
(normal)
Hi Kay, I presume you are a woman, and if so the urine is vastly over – collected: more than 24 hours. I say this because 33.6 mg of creatinine/24 hr/kg body weight would be found in only an Olympian woman athlete – all muscle, no fat, massive muscle development. Normal values range around 18 – 22 for young fit women. If we assume an average for the young fit woman of 20 mg/kg/d given your 33, your urine volume is really 20/33 or 0.6 times 1.4 liters or 0.85 liters, a very low value indeed. That low volume is concentrating your reasonable calcium excretion and rather ample oxalate making the high SS for CaOx and CaP. I would suggest a new 24 hour collection with avoidance of over collection. Regards, Fred Coe
Hi, about 6 months ago I was diagnosed with renal tubular acidosis after passing stones. My nephrologist prescribed potassium citrate 15 meq 2x per day. The medication is overall tolerated, though at times it does cause some stomach/digestive discomfort.
I recently did a 24 urine collection to see how the medication was doing. The results came after my follow up, but my nephrologist didn’t seem to think I should increase the dosage (having only seen my bloodwork and not the 24 urine collection) since it was causing some discomfort. I’m wondering, if after looking at these results, if the dosage should be increased?
They are as follows (only abnormal results listed):
UR Citrate 24HR 18/mg
UR Chloride 24HR 260
UR Creatinine 24HR 2157.8 mg
UR Sodium 24HR 306
Oxalate 39mg/24HR
UR Phosphorus 1499.5mg/24HR
UR Sulfate 42
UR Uric Acid 24 HR 788mg
UR Volume 3520 mL/24HR (I drink about 80 oz of water per day)
Abnormal blood results are as follows:
Chloride 113mmol/L
Carbon Dioxide 20mmol/L
GFR 59ml/min
Any insight you can give is greatly appreciated!
Hi Melissa, Your blood does seem actually abnormal as in RTA. Take a look at what RTA looks like and decide. Your CO2 is low and chloride high. Your urine results are too incomplete for me to work with: no pH, ammonia, potassium; certainly your citrate is essentially 0 at 18 mg/d, in fact I doubt the lab could have measured it. I could try to be more helpful if I had the missing numbers, but I note that kidney function is a bit low, and your blood abnormalities untreated, so at the very least I would think – if this really is distal RTA – one would want to bring them more into the normal range. Please send along more complete information, if you wish. One wonders why RTA now, as most are hereditary. Regards, Fred Coe
Hi Dr. Coe,
Please help me with a mystery regarding 24 hour urines. Litholink’s reported ‘Vol 24’ values vary widely from the actual volume of my collections. Differences up to 0.5 liter are common, but others are within 0.01 liters. For example, my latest measured 3.2 liters, but the reported ‘Vol 24’ was only 2.7 liters.
Questions – Any ideas about why the two values differed so much? And can I trust the test results when the volumes differ by a whole ½ liter?
Thanks for your time, Kenny.
P.S. More info…
I carefully followed the instructions, collected for 24 hrs, and shook well before pouring the sample to mail.
My seven Cr 24 values for the last two years are all within 20% so no red flags there.
Hi Kenny, Litholink measures urine volume by internal standard dilution. When you put the preservative into the collection, it also contains an exact amount of a harmless salt whose concentration is measured in the final urine aliquot you send back. The concentration is amount of salt added/volume of urine; since the amount added is known exactly, volume of the 24 hour urine it dissolved in is amount of salt added/concentration. The collection container volume estimates are far more variable and less reliable than the dilution system – we checked them against each other. Regards, Fred Coe
PS.. I also seem to tend to have ecoli UTI
Hi TB, Often, many stones lead to infection. The best hope is prevention of stones. Fred
Hi Dr. Coe–I’m a 55 y.o. female with a solitary kidney since age 1, and oh does that kidney serve me well! I’ve never had a stone or health problems until 2.5 years ago (coinciding with menopause) when an ultrasound showed a 3mm stone. It grew to 4mm, another 1mm stone appeared, and my urologist did ESWL on it in Sept ’19 (they couldn’t find the 1mm one).
I’ve never passed a stone (that I know of), even after lithotripsy, so we still don’t know the composition of my stones.
I did a 24 hr urine just before my ESWL, and it was unremarkable according to my uro except for the low volume (1.5L).
I’ve worked hard at increasing my fluid intake (pretty easy during a pandemic), but it turns out I have a non-obstructing 3 mm stone again (by CT scan), and I’m told it’s new. So I requested a 2nd 24 hr urinalysis, and the results that I received today are again “unremarkable” according to the office. They are as follows:
24 Hr Urine: 3.16L, pH 6.5,
uric acid 284 mg/day,
Ca++ 221 mg/day (this is up from 135 mg/day in 2019),
Na+ 66 mEq/day (that’s not a typo…I’ve long avoided salt, but I’ve worked to lower my sodium intake since it was 93 mEq/day in 2019),
citrate 471 mg/day (this is down from 689 mg in 2019),
phosphorous 632 mg/day,
Oxalate 14 mg/day (not a typo either),
Mg 83 mg.day, creat 0.6 g/day,
Mg/g creat 130 mg/g creat.
Blood:
Ca++ 10.0 mg/dL
uric acid 3.9 mg/dL
phosphorous 4.2 mg/dL
GFR>60
I’ve worked so hard at making sure I drink a ton of fluids, and my urine volume shows that, but I feel entirely defeated. My uro wanted me to increase my dietary calcium back in 2019, but it looks like all it did was raise my urine calcium. The office has told me that my labs are all great and to “keep doing what you’re doing, and we’ll see you in 6 months.” While I’m thankful to have terrific labs, what I’m doing is clearly not working as well as I need it to. At least not for an individual with a solitary kidney.
Again, we don’t know the composition of my stone. I have an appointment with a nephrologist in a month in hopes of figuring out why I’m still getting stones and am wondering if you can give me any insight as to what to ask for, what to look at, etc…
Hi Mary, Of interest your stones began later in life. Your urine calcium is very high being 221 mg with a urine creatinine of o.6 gm or 368 mg/gm creatinine – should be about 140 mg/gm creatinine. Urine pH is a bit high at 6.5 and your one serum calcium is 10 – right at the upper limit of normal. The best fit is primary hyperparathyroidism that came on later in life, the alternative is rapidly progressing bone mineral loss. I would have your physicians evaluate for this getting fasting morning serums for calcium and PTH on at least three separate mornings. Likewise, bone mineral density. So your labs are not ‘great’ and you probably have significant cause for new onset stones. But I am far away, not in possession of your entire record, and therefore merely commenting. Your personal physicians are entirely responsible for your care, and what I say is for them to consider as they think best. Regards, Fred Coe
Thanks so much, Dr. Coe! I’m having a bone density scan soon and will ask for repeat Ca and PTH tests with fasting (my PTH was 41 pg/ml last month, but it wasn’t fasting).
Hi Dr Coe,
My litholink 24 hr urine had me concerned. It said in the interpretation of lab results I am borderline hypocitraturia and to consider distal renal tubular acidosis which has me very nervous. My dr didn’t address those thing just said to increase my citrus acid and eat a lemon a day. Here are my results:
Urine volume 2.70
Ss caox 3.24
Urine calcium 159
Urine oxalate 24
Urine citrate 533
Ss cap 0.95
24hr urine ph 7.030
Ss Uric acid 0.03
Urine uric acid 0.292
Hi Christen, The LL algorithms seem a bit pushy here given your citrate level of 533. As I wrote them, with Dr Asplin, when I owned LL and after I sold it to LabCorp, I can take some criticism for them. Ignore the RTA warning. Fred
Good morning. My 24hour is completely confusing to me. Looks like it could create every stone. Summary Stone Risk Factors
SAMPLE ID: S26496047 ANALYTE
Urine Volume SS CaOx Urine Calcium Urine Oxalate Urine Citrate SS CaP
PATIENT COLLECTION DATE: DECREASED RISK
03/05/2021 1.61
INCREASING RISK FOR STONE FORMATION
(liters/day)
(mg/day)
(mg/day) (mg/day)
36 1254
9.67
362
2.85
24 Hour Urine pH
SS Uric Acid
Urine Uric Acid (g/day)
6.525
Interpretation Of Laboratory Results
0.30
0.716
Suboptimal urine volume. Increase urine volume above 2.5 liters.
Hypercalciuria. Exclude hypercalcemia, Vit D excess, sarcoidosis, hyperthyroidism and malignant neoplasm. Treat with diet sodium 2300 to 3500 mg/day, calcium 800-1200 mg/day from food; protein 0.8 to 1.3 gm/kg/day (see PCR value on Dietary Factors table). Thiazide if needed. Recheck at 6 weeks.
Borderline hyperoxaluria. May contribute to calcium oxalate stone risk. Can be caused by high oxalate or low calcium diet, or vitamin C supplements. Treat with low oxalate diet and diet calcium of 800 to 1200 mg/day. Recheck at 6 weeks.
High urine pH. High urine pH can promote calcium phosphate stones. When coupled with low urine citrate consider distal renal tubular acidosis. When using alkali supplements (citrate or bicarbonate) manage urine volume and urine calcium to maintain SS CaP less than 2.0.
Mild hyperuricosuria Can cause calcium oxalate stones. Reduce poultry, fish and meat protein to 0.8 to 1.3 gm/kg/day (see PCR value on Dietary Factors table). Recheck at 6 weeks. If stones are clinically active and diet measures fail consider allopurinol 150 – 300 mg daily.
Moderate CaOx stone risk. If stones are calcium oxalate and actively forming, manage urine volume, calcium and oxalate to lower SS below 4.
High CaP stone risk. If stones contain >15% calcium phosphate and are actively forming, manage volume and calcium to lower SS below 1.2.
Page 2 of 4 Version:9.4.6.7084
Dear Jennifer, Oh My! When I owned Litholink I wrote all that for the computers to use, but never meant it so pile up so. Basically it is telling you to drink more, and lower diet sodium in order to lower urine calcium losses, then retest to see if things are better. The mild increase in oxalate may be from foods or too low a diet calcium – when you lower diet sodium you can eat more calcium and lower oxalate without raising urine calcium. Take a look here.Your urine pH is high, so stones may have phosphate in them. True, but the treatment is much the same– that is in the huge printout you got. Not so bad as it looks. Regards, Fred Coe
Thank you so much! I appreciate it.
I have just one more question if you don’t mind. I’ve been trying to find some research on it… will, D-amphetamine salts – “generic adderall”, raise the sodium in your body and then your calcium causing stones? I do take prescription adderall, I wondered if this had an effect? Thank you so much for your time.
Hi Jennifer, In modest doses I know of no connection. These drugs raise blood pressure, so be sure yours is fine <120 systolic. Regards, Fred Coe
Hello Dr. Coe,
I am female 49. I am so confused about all my levels. I have had PTH levels high but not real high 10.6 was highest, my D is natural low under 6 if I don’t take 50iu every 5 days, it stay around 40, my blood phosphorous is sometimes low 2.2, but the endo ran rare diseases for that and it was normal, my hematocrit is high and red blood cells, and hemoglobin, but not my wbc. my 24 hour urine has been as high 1116 and phosphorous 3732. Then an ultrasound showed I had kidney stones with measurements, but ct 5 days later showed none with no evidence of any passing.
The urologist ran a 24 hour urine and here are the results.
Urine volume – 1.61
As CaOx – 9.67
Urine calcium – 362
Urine oxalate – 36
Urine Citrate – 1254
SS CaP – 2.85
24 hr Urine PH – 6.525
SA Zurich Acid – .30
Urine auric Acid (g/day) .716
Dietary factors
Na24 – 200
K 24 – 69
Mg – 157
P 24 – .665
Nh4 24 – 25
Cl 24 – 210
Sul 24 – 29
UUN 24 – 6.97
PCR – .7
Family history of stones 1 sister with lupus my ANA has never been positive. I do have hashimotos, there is a possibility of Multiple Sclerosis. Been following for 5 years.
I have only had 1 stone in 2016 that was 10mm. Lithotripsy.
Also when I was young I had many kidney infections, bladder infections, doctors tried to increase my bladder size because my bladder was so tiny.
I live in Colorado. If you think I should see a kidney specialist please let me know. I had a 24hr urine test many years ago and there was nothing about idiopathic hypercaliciuria but the endo thinks there is now. Does that develop over time?
Hi Jennifer, Lets focus on the numbers this time – see my last note. You have high urine calcium 362, and sodium 200 mEq (this is your diet). But you mention 10.6 and I believe that is your blood calcium – is it not? If so you may have primary hyperparathyroidism, and that is curable and needs special attention. Here is my newest version of that disease. You need to check back over all your blood calciums, and read the article. If there is any suspicion, the article and video tell you what to do. Do it. Regards, Fred Coe
Hello, Dr Coe
I am 32 y o male.
I have three time reacurance of kidney stones. Currently having 5-6 mm stones in my kidney. As suggested by my doctor I did 24 hr urine test. The lab report values are as under.
24 hr Urinary Uric Acid – 547.1 mg/day
24 hr Urinary Oxalate – 43.0 mg/day
24 hr Urinary Calcium – 244.44 mg/day
24 hr Urinary citrate – 980.0 mg/day
Urinary pH- 4.8
24 hr urine volume – 3.88 ltr
24 hr Urinary sodium – 197.9 mmol/day
24hr Urin Phosphorus- 356.96 mg/day
24hr Urinry magnesium- 65.96 mg/day
CaOx – 3.798
CaHPO4 – 0.022
UA – 1.085
24hr Urinry potassium- 38.8 mmol/day
24 hr Urinry creatinine- 897.44 mg/day
#Other reports are as under
Parathyroid Hormone (intact) – 69.5 pg/ml
Serum Calcium (Ca+) – 9.0 mg/dL
Serum Uric Acid – 5.9 mg/dL
Serum creatinine – 0.94 mg/dL
My doctor said the reports are normal and prescribed me to take Potassium Citrate and Magnesium Citrate Oral solution And to drink plenty of water to remove it.
I know I m drinking plenty of water. My question is why I have reacurance of stone every 2 yr and is that everything normal? What could I do to permently cure it. Thank you sir dr.
Hi Karan, the most striking measurement is the pH of 4.8 which is a major risk for uric acid stones. You do not say what your stones are made of, but that is crucial. Your physician can measure the density of your stones from your CT using the routine software we all have, and if they are <600 HU uric acid is very likely. I would go there first. He/she prescribed citrate perhaps because of the low pH. Regards, Fred Coe
Hi Dr. Coe!
I was thrilled to find this article yesterday upon receiving my 24 hr litholink report! I am a 51 y.o female. I had a stone 30 years ago and figured it was a one and done until recently. I had lithotripsy last week and am turning in stone fragments today for analysis. It was discovered in January that I have several stones on both sides. Also, medullary nephrocalcinosis was noted on my CT report. I will just list my out of range results here.
Urine volume was 2890 mL
Calcium Oxalate saturation was low at 3.38
Calcium was high at 375
Oxalate low at 15
Citrate low at 545
pH high at 6.446
Phosphorus low at 548
Chloride low at 65
Calcium/Kg Body weight high at 7.5 (110lbs)
Calcium/Creatinine Ratio high at 420
I have also had a slightly elevated serum calcium at 10.6 (range went to 10.4) and Ionized calcium also slightly at 1.25 mMol (range went to 1.2) Normal PTH at 17 and Vit D at 53.
I live in Chicago suburbs and have a call into your office to get an appointment in the Stone prevention clinic and I have a call scheduled with Jill Harris on 3/30. I also have an appt. with a more local Nephrologist for 4/14.
My question to you is this: Should I look further into parathyroid? It seems unlikely with a PTH of 17 but I know there can be unusual presentations. I have had very strange muscle issues for about 5 years and also the cardiac arrythmias, which I have just accepted as a “new normal” of sorts.
I would appreciate any feedback you have for me!
Hi Renee, If you are coming to see me, I can more or less solve this problem for you directly. With the high blood and urine calcium primary HPT seems likely. The lowish PTH may be an important clue to an alternative diagnosis but often it is an artefact – serum PTH is unstable and values can fall. Plasma PTH is stable. I understand from my office you have been in contact and my secretary will be calling you this afternoon to arrange proper lab evaluation prior to our visit so I can resolve things then. Possibly, you might want to put off an additional nephrological consultation until we are done, as he/she might want our results and my report in advance. Regards, Fred Coe
Thank you so much for your reply! I would be thrilled to come see you and it seems as if you have a plan to figure this out. That would be a blessing. Right now, my GP says I need an endocrinologist and my Uro says I need a nephrologist. I have appointments for both, which I would gladly put on hold to see you. I am having a bit of trouble, however, scheduling. I’ve been trying for three weeks to get an appointment and I get as far as Benita’s voice mail, but she has never called me back. (You don’t need to publish this response, I”m just hoping this gets to you) I will try again on Monday, If you can help at all, I would surely appreciate it.
Hi, I will copy Banita with your entire comment, as I am sure somehow she did not get the communication. Fred
One more thing, Dr. Coe.
I was just getting all of my labwork together and I noticed that on Feb 4 of this year my GFR was 72. On Feb 26, just three weeks later, GFR was 57. Is that even possible? It’s got me a little worried. Thank you for any perspective you might have.
Hi Renee, My secretary told me today that she is in touch with you about an appointment, so we can discuss all this in person. Fred
Thank you for all of your wonderful work, Dr. Coe! I am a 33 year old male and had my only ER kidney stone episode last December where I was diagnosed with two ureteral stones. I passed the larger one and it came out to be: 40% Calcium oxalate monohydrate 40% Calcium oxalate dihydrate 20% Calcium phosphate (apatite). Status of smaller stone is unclear. I have incorporated diet changes since then including significantly increasing my calcium intake and less significantly controlling oxalate. I just got my 24-hour urine results from Litholink which are more a reflection of my new habits (high fluids, adequate calcium, mild oxalate control). It is difficult to go back to old bad habits after working hard to fix them! 🙂
Here are my results:
Urine Volume: 3.35 litres/day
SS CaOx: 3.01
Urine Calcium: 230 mg/day
Urine Oxalate: 30 mg/day
Urine Citrate 309 mg/day
SS CaP: 1.26
24 Hour Urine pH: 6.780
SS Uric Acid: 0.08
Urine Uric Acid: 0.641 g/day
Na 24: 174 mmol/d
K 24: 92 mmol/d
Mg 24: 77 mg/d
P 24: 0.937 g/d
Nh4 24: 49 mmol/d
Cl 24: 223 mmol/d
Sul 24: 23 meq/d
UUN 24: 8.40 g/d
PCR: 0.9 g/kg/d
Weight: 69.5 kg
Cr 24: 1141 mg/d
Cr 24/Kg: 16.4 mg/kg/d
Ca 24/Kg: 3.3 mg/kg/d
Ca 24/Cr 24: 201 mg/g
My lab report says to consider distal renal tubular acidosis, but from previous comments here and your article on DRTA coupled with my blood chemistry values (Chloride: 103 mmol/L, CO2: 29 mmol/L), it doesn’t seem like that should be a concern. Do you think simply adding more citrus fruits to my diet will be enough to reduce my stone formation risk? Any other inputs on my results will be much appreciated.
Best regards,
Rahul
Hi Rahul, You are a remarkable example of what we have observed in people prone to calcium phosphate stones – very high urine pH (6.78) a very high urine ammonia (49 mEq/d, main renal acid loss) compared to sulfate (23 mEq/d, main systemic acid load) and low urine citrate (309 mg/d). This article details the calcium phosphate stone former story – you are not as yet officially a CaP stone former but are on the way. The reason for the high ammonia and low citrate appear to be genetic, but that is still conjecture. I suggest you show your physician the linked article, as treatment is tricky. Certainly more alkali is not an ideal move. Regards, Fred Coe
My citrate level came back at 3038 level today. My urologist says in all his years he has never seen a citrate number so high. He asked if I took supplements, I do, magnesium and fish oil daily and iron and potassium as needed. I also take hctz. He gave me a script for vitamin b6. I’m just confused and don’t know what all this means. He rushed me in and out quickly.
Hi Megan, any alkali load – magnesium carbonate, potassium citrate or bicarbonate as examples, but you would need a lot! Metabolic syndrome is a more likely cause – do any of its components relate to you: high BMI, hypertension, elevated blood lipids, insulin resistance? I do not know what the b6 will be for. If you have stones, and have had 24 hour and blood testing, you need to look for the cause of your stones: what crystals are in the stones, are urine supersaturations increased for those crystals, if so why? Regards, Fred Coe
Hi! Would love your help with my Litholink results. Trying to be a living donor and found two small stones in lower pole of kidney. Never knew I had them.
Vol 2.77
SA CaOx 4.42
Ca 24 389
Ox 24 30
Cit 24 675
SS Cap 1.90
PH 6.570
SS UA .20
UA 24 .900
Na 24 277
K 24 73
Mg 24 118
P 24 .992
Nh4 24 50
Cl 24 278
Sul 24 62
Uun 24 14.12
PCR 1.6
Cr 24 1321
Cr24/kg 20.8
Ca 24/kg 6.1
Ca 24/ cr 24. 295
Am I a stone risk? Or is it safe to donate a kidney. Interpretation says Hypercalciuria. High urine ph. (Which didn’t show on regular 24 hour urine) Hyperuricosuria. And moderate CaP stone risk. Seems like a lot of info. I think they were just doing test to see if I’m a cystine stone former which says negative but what is all this other stuff.
Hi Lisa, you obviously have genetic hypercalciuria: Ca 24 389 (should be around 120, certainly below 200; Ca 24/ cr 24. 295 (should be below 140). So you have increased risk for stones and carry a common multigene abnormality. The high pH promotes calcium phosphate as opposed to calcium oxalate stones. You have 2 stones. If anyone asked me I would say kidney donation is not an ideal for you – I would be negative about it. However, I am not your pre-transplant nephrologist and know nothing about the urgency or other complexities of your donation, and therefore comment out of ignorance apart from the stones and hypercalciuria. I might say your PCR value of 1.6 suggests a very high protein intake that can raise urine calcium, and perhaps a lower intake might reduce your urine calcium, but you do have stones, too. Regards, Fred Coe
Hi Dr. Coe – I really enjoy reading your articles! I’m a 49 year old male retired military working overseas. In 2017 had some random labs done and found out I have high uric acid. It seems to fluctuate between 416 -460 micromol/L. A few months later I found out via ultrasound I had a 3mm stone. Direction was to increase fluid intake. Fast forward to 2021, an ultra sound showed a 3.4mm stone. My GP requested the following labs done with results:
Kidney Stone, Urine Saturation (mL/24hr):
Urine Volume (Preservative) = 2,400
Calcium = 1.5
Sodium = 125
Phosphorus = 14
Uric Acid = 1.7
Potassium = 43.2 (mmol/24hr)
Chloride = 113 (mmol/24hr)
Citric Acid = 2.4
Oxalates = 251 (umol/d)
Magnesium (24hr) = 1.69
Sulfate = .4
Cystine = 49 (umol/d)
Osmolality = 207 (mmol/kg)
Creatine = 69.6
Calcium Oxalate (ratio) = 1.08
Brushite (ratio) = .14
Monosodium Urate (ratio) = .67
Uric Acid (ratio) = .40
Struvite (ratio) = .01
Values:
PH = 6.1
Calcium = .06 (mmol/L)
Sodium = 52 (mmol/L)
Phosphorus = 1
Uric Acid = .1
Potassium = 18 (mmol/L)
Chloride = 47 (mmol/L)
Citric Acid = 1.02 (mmol/L)
Oxalates = 103 (umol/L)
Magnesium = .07 (mmol/L)
Sulphate, urine = .2 (mmol/L)
Cystine, urine = 20 (umol/L)
Creatine, urine = 2.9 (mmol/L)
Ammonia, urine = 15,060 (ug/dl)
Ammonia, urine = 21 (mEq/24hr)
I have been referred to a Kidney Stone clinic here (United Arab Emirates). My question is what questions should I be asking the doctors here based off the results of my labs? Do you see any concerns I should be asking about? JD
Hi JD, A lot of numbers and presented and arranged in a way that is not too clear. Urine Volume (Preservative) = 2,400
Calcium = 1.5 ? mmol/d, would be normal
Sodium = 125 ?mmol/d, reasonable
Phosphorus = 14?? units
Uric Acid = 1.7?units
Potassium = 43.2 (mmol/24hr) fine
Chloride = 113 (mmol/24hr) reasonable
Citric Acid = 2.4
Oxalates = 251 (umol/d) not very high
Magnesium (24hr) = 1.69 mmol/d?? reasonable
Sulfate = .4
Cystine = 49 (umol/d)
Osmolality = 207 (mmol/kg) dilute urine
Creatine = 69.6?units
Calcium Oxalate (ratio) = 1.08 – low!
Brushite (ratio) = .14 below 1, no risk
Monosodium Urate (ratio) = .67
Uric Acid (ratio) = .40 below 1, no risk
Altogether the results I can interpret seem to say no risk, so perhaps you made your stone under conditions different from when the collection was made. But there are missing units, so I cannot be fully sure. Regards, Fred Coe
help……what does all this mean
dr. just said he was going to put me on a diuretic 55mg twice a day and to majorly increase my fluid
urine vol. = 1.77, ss ca ox 6.98, urine cal=301, oxalate=24, citrate 828, sscap 2.62, urine ph6.682, ss uric acid 0.11, urine uric acid 0.398
I have had several calcium oxalate stones
what can I do to stop this . 60 yrs old , 200 lbs,
Hi Lisa, you have a high urine calcium at 301 mg/d, and a low urine volume below 2.4 liters (the risk level for volume). Your SS CaP of 2.62 puts you at risk for calcium phosphate stones – are you really sure about the stone analysis. Given stones began later in life, the most worrisome possibility is that you have primary hyperparathyroidism, and that can be cured. Possibly you are losing bone mineral at a high rate, and that is raising urine calcium – you need a bone DEXA scan to find this out. Regards, Fred Coe
Hi Dr Coe,
Thanks for providing such valuable resources when it comes to kidneys and kidney stones. I had a Calcium Oxalate stone removed in February, my first ever at 45 yrs old. After two months of increasing my water intake to nearly a gallon a day, I had a 24 hour urine test. The results are confusing to me, largely because my Calcium Oxalate Saturation levels seem to be low, while my Calcium level seems to be quite high. Seems contradictory? Here are my results, any interpretation or advice would be greatly appreciated. Thanks!
Urine Volume (Preserved) 4440 High mL/24 hr
Calcium Oxalate Saturation 2.63 Low 6.00-10.00
Calcium, Urine 329 High mg/24 hr 450
Calcium Phosphate Saturation 0.47 Low 0.50-2.00
pH, 24 hr, Urine 6.109 5.800-6.200
Uric Acid Saturation 0.22 <1.00
Uric Acid, Urine 563 mg/24 hr <800
Sodium, Urine 137 mmol/24 hr 50-150
Potassium, Urine 63 mmol/24 hr 20-100
Magnesium, Urine 118 mg/24 hr 30-120
Phosphorus, Urine 875 mg/24 hr 600-1200
Ammonium, Urine 51 mmol/24 hr 15-60
Chloride, Urine 141 mmol/24 hr 70-250
Sulfate, Urine 57 meq/24 hr 20-80
Urea Nitrogen, Urine 10.62 g/24 hr 6.00-14.00
Protein Catabolic Rate 0.9 g/kg/24 hr 0.8-1.4
Creatinine, Urine 1603 mg/24 hr Not Applic.
Creatinine/Kg Body Weight 17.2 mg/24 hr/kg 11.9-24.4
Calcium/Kg Body Weight 3.5
Hi Andrew, You have a high urine calcium loss (329 mg/d), possibly genetic, and have reduced your SS values by so high a urine volume. No doubt you formed your stones when urine volumes were considerably lower. You might lower urine volume to 3000 ml/d and still have safe SS values. All the rest of your study looks rather reasonable, especially the lowish diet sodium of 137 mEq/d. Regards, Fred
Thanks so much for your response Dr Coe. Yes, I believe my urine output was around 1L per day previous to 2021. Again, thank you for the analysis, it is much appreciated – Andrew
Thank you for the information. I have had two 24hr collections done. I’m wondering if going to a plant based diet (milk elimination) has increased my risk for oxalate stones because the lower calcium does not supply enough calcium to bind with the oxalate. Is this a valid concern? Or do I need to just continue lowering my oxalate intake, e.g. spinach, kale, etc. Here are my collection results.
Urine volume: 2.11
SS CaOx: 7.53
Urine Calcium: 127
Urine Oxalate: 70
Urine Citrate: 705
SS CaP: 0.99
24hr Urine pH: 6.468
SS Uric Acid: 0.26
Urine Uric Acid: 0.671
Thank you
Bill
Hi William, I believe your low calcium diet has raised your urine oxalate – a very common occurrence. I would add back a normal amount of diet calcium right away and repeat the 24 hour collection – urine calcium will rise, oxalate will fall, perhaps low enough it is no longer an issue – and you can focus on whatever is really wrong. Regards, Fred Coe
My Stone Risk Factors are:
Urine Volume: 2.11
SS CaOx: 7.53
Urine Calcium: 127
Urine Oxalate: 70
Urine Citrate: 705
SS CaP: 0.99
24 Hr Urine pH: 6.468
SS Uric Acid: 0.26
Urine Uric Acid: 0.671
Should I increase my dietary calcium, lower my dietary sodium, and increase my fluid intake? What else can I do?
Hi William, I believe I answered you in my other response. Fred
Volume
1700 mL/24 hr
Higher Than Normal
600-1600
Calcium
312.8 mg/24 Hr
Higher Than Normal
100.0-300.0
Sodium
160 mmol/24 hr
39-258
Phosphate
1314.1 mg/24 Hr
Higher Than Normal
400.0-1300.0
Urate
772 mg/24 Hr
Higher Than Normal
250-750
Potassium
60.4 mmol/24 hr
25.0-125.0
Chloride
109 mmol/24 hr
Lower Than Normal
110-250
Citrate
493 mg/24 Hr
320-1240
Oxalate
32 mg/24 Hr
Higher Than Normal
4-31
Magnesium
95 mg/24 Hr
12-293
Sulfate
27 mEq/24 hr
0-30
Cystine
17.70 mg/24 Hr
10.00-100.00
Osmolality
493 mOsm/kg
300-900
Creatinine Calculated
1655.8 mg/24 Hr
800.0-1800.0
pH
6.0
Ammonia
25 mEq/24 hr
Calcium Oxalate Saturation
8.37 ratio
Higher Than Normal
0.00-6.00
Calcium Hydrogen Phosphate Dihydrate (Brushite)
3.09 ratio
Higher Than Normal
0.00-3.00
Sodium Urate Saturation
4.38 ratio
Higher Than Normal
0.00-4.00
Urate Saturation
1.85 ratio
Higher Than Normal
0.00-1.20
Magnesium Ammonium Phosphate Hexahydrate (Struvite)
0.02 ratio
Any thoughts?
Hi Megan, No thoughts, as you offer no basis for thinking, but your numbers suggest genetic hypercalciuria and low urine volume. Your high SS values for calcium oxalate and brushite are important stone risks. Regards, Fred
I just received my 24-hour results and meet with my doctor soon. I’m wondering what all this means in the meantime. In February I went to the ER and found that I had a 7 mm stone in my left urethra. When I saw the urologist he said I also had many stones in my kidneys. I had Ureteroscopy done in March where they were able to get all of the stones out of my kidneys as well as the 7mm one. They sent 3 stones (from 1 mm to 9mm) to be analyzed and found that they were 70% calcium oxalate monohydrate, 10% calcium oxalate dihydrate, and 20% calcium phosphate. Can you help me understand all of these numbers. (I’ve included my Litholink numbers below)
Urine Volume 2.48
SS CaOx 4.80
Urine Calcium (mg/day) 261
Urine Oxalate (mg/day) 23
Urine Citrate (mg/day) 351
24 Hour Urine pH 6.190
SS CaP 0.82
SS Uric Acid 0.27
Urine Uric Acid (g/day) 0.461
Hi Suzanne, You have high enough urine calcium to raise risk of stones, and low enough urine citrate to do the same. We have found this is very typical of women calcium oxalate stone formers (I have not written our research into an article for the site, it is still a research publication. You may be an ideal candidate for potassium citrate to raise urine citrate and low diet sodium – 1500 mg/d – to lower urine calcium. See if your physicians might not agree. Regards, Fred Coe
Dr. Coe – I have just received my 24 hr test.
Vol 1.96
SS CaOx 8.80
Ca 24. 315
Ox 24 30
Cit 24. 746
SSCaP. .62
pH. 5.64
SS UA. .98
UA 24. .502
I was told my risks are the 8.80 SS CaOx, the 315 Urine Calcium and pH of 5.64 was borderline low for Uriel acid stones.
I have had CaOx stones.
I do not take supplemental Calcium. I have read the Harvard list for oxalate content and I’m ok with that.
What are your recommendations, please?
Do you need other values?
Thank you.
Kate
Hi Kate, Your urine calcium is high and if your serum calcium is normal I presume you have genetic (idiopathic) hypercalciuria. Usual treatments are low sodium diet – to lower urine calcium – and thiazide type diuretics to lower urine calcium more. This is a common problem. Bone mineral needs measuring as it can be lost in the urine and bone can fracture in some cases. Regards, Fred Coe
Hello Dr. Coe,
Thank you for your generosity! You are very kind to share your expertise.
Vol 24 4.71
SS CaOx 2.93
Ca24 420
Ox24 31
Cit24 1100
SS CaP 1.74
pH 6.881
SSUA 0.07
UA24 1.012
also:
P24 1.172
Ca24/kg 4.6
Ca24/Cr24 273
Hi Jen, Your urine calcium is very high and your urine pH, too. This usually leads to calcium phosphate stones. The high urine calcium can be genetic or from some specific cause. Your physicians need to sort that out. Regards, Fred
Greetings Dr. Coe – and thank you in advance for all your help on this forum 🙂 Like everyone else here, I’m confused about my 24 hour results so if you have any tips, I’d be so grateful!
I am female, 54, 5’10 and 185# and train 6 days a week. I had 9mm stone surgery in April – renal sono says “multiple stones present” and hydronephrosis.
Urine Volume 3.07
SS CaOx 5.64
Urine Calcium 159
Urine Oxalate 70
Urine Citrate 539
SS CaP 0.60
pH 6.291
SS Uric Acid 0.32
Urine Uric Acid 0.851
Hi Kimberly, your urine oxalate is eye catching – perhaps a mix of high plant intake with lack of corresponding diet calcium at such meals – needs to be lower. With 3 liters of urine volume things can seem good but people who train 6 days a week risk periods of low urine volume 6 days a week, possibly another factor in your stones. Usually a main reason for high oxalate is as in the link – inadequate diet calcium intake or placing of calcium intake away from the main high oxalate foods. Here is our high oxalate food list – very long, but focus on the initial figures that highlight the worst foods. Regards, Fred Coe
Thank you so much for the tips, Dr. Coe – much appreciated!!! 🙂
Good day-I am 69yo and a Family doc, I have been plagued with kidney stones for years. I have passed 7 stones the last almost 2 years ago requiring hospitalization. Recent CT scan still revealed multiple stones with largest 11mm. Previous stone and recent stones have been CaOxalate stones. Being a vegetarian, I have always had low protein in my diet and plenty of fruits and vegetables. Almost every meal includes cheese to keep up with protein and bind with any oxalate in my meals. I have stopped almost all high oxalate foods(many of my favorites) and only have something sweet for special occasions-a few times a year. The fluids have become an issue as I have increasing urgency and drink 2-3 liters a day unless I have to go out. I restrict my intake of fluids to 5 hours before I go to sleep so I do not have to get up more than 2-3 times.
Recent 24 hr. Urine analysis:
Ca 175mg
Oxalate 31g
UA 519
Citrate 882mg
Na 132 meq/d
Sulfate 19mmol/d
Phos 901mg/d
Mg 127mg/d
Ammonia 34 meq/d
K 53meq
Cr 1,635
CaOx 1.02
Brushite 0.3
NaUrate 0.79
Struvite ).04
UA 2.30 (H)
I’m not sure what else I can do to reduce ‘my fertility’ for producing kidney stones. Appreciate your thoughts.
All the best-Fred
Hello Dr Arredondo, I think the clue lurks in your history: “The fluids have become an issue as I have increasing urgency and drink 2-3 liters a day unless I have to go out. I restrict my intake of fluids to 5 hours before I go to sleep so I do not have to get up more than 2-3 times.” Crystals form when supersaturation rises – repeated periods of reduced urine volume are a setup for stones. I also notice SS uric acid above 2, a very high number, suggesting your urine pH must be below 6 – also you do not show the 24 hour urine volume. Potassium citrate might be a good idea even though your stones are calcium oxalate if urine pH is indeed low enough to cause UA SS of 2.3, and of course the low volume needs tending to – I need not elaborate. Best, Fred