MePhysicians can only do so much with stone prevention because a large part of the work can only be done by patients themselves.

The Five Steps to Stone Prevention, the two articles on how to read your 24 hour laboratory reports for calcium and uric acid stones, and the article on how to be a successful kidney stone patient are the reference materials you need to accomplish your part of your personal stone prevention program.

It is now time to pull these four articles together into an organized approach that any patient can follow.


Before your visit to decide on prevention Read the article on how to be a successful kidney stone patient, where  you will find lists of materials to bring with you. 

Know your stone type(s).

Get the right blood and 24 hour urine testing.

Read your own 24 hour urine laboratory reports and make notes so you will be fully prepared to make use of what your physician knows

Perform what I call the ‘Great Integration’ and have it ready as a key part of your discussion with your physician.


How, exactly, do you prevent what you do not know?

Stone analysis is the foundation of your prevention.

Find past analyses. If you have stones in your possession, get them analyzed.

If there never have been any analyses and you have no stones, make a good guess. Part 1 of Five Steps details an approach, so read it now if you do not know your stones.

Do not give up easily. Someone, somewhere, may have your report. If all you can do is guess, guess as best you can. Have your physician guess, too.


The needed blood tests can be obtained from any certified laboratory. Be sure they are fasting.

Proper 24 hour urine testing is best done through one of the national vendors of such products. Local hospital laboratories are not ideal and often simply send the urine out to such vendors with high possibility of adding errors. Vendors provide home collection and mailback materials, and issue a graphic and complete report of all measurements including supersaturations.

Much of the value of your 24 hour testing is determined by your behavior. You need to collect so the results reflect your average life conditions. If you show off and drink a lot, you will be fooling yourself. If you collect only on a weekend day, likewise. Two collections are much more valuable than one. If a collection goes badly – loss of a sample, uncertain timing, throw it out and do another – it costs nothing and prevents mistakes.

You are the one who times your collections. Make a copy of your start and stop times, so you can compare your results to those in the final report. Sometimes there is a mistake in transcribing.

You will measure the urine volume in many cases, or can measure it from markings on the container. Write them down in case there is a question of errors. The largest vendors, Litholink (a branch of LabCorp) and Quest actually infer the 24 hour urine volume and do not use your measurements in most cases. They add one or another proprietary marker to the collection container and measure its concentration. This latter tells them the volume in which the material has been diluted. That volume is the 24 hour urine volume. Here and there, though, if you have measured carefully your measurements may help resolve problems when the multiple samples from you fail to match in their completeness of collection. For your measurements to be useful, you need to read the volume as precisely as possible – get as specific a reading from the measuring scale as you can – and write the results down.


As I launch into this I want to make clear my intent is to enable patients to make the best use of their physician visits. You need a physician, but you can do a lot before the visit to become thoughtfully informed and thereby be a more useful partner. If you have thought through your own information the time you have together can be used for more detailed explanation and less for routine matters you can do beforehand for yourself.


Find the 24 hour urine creatinine excretions and see if they match within about 15 percent. If not, one is wrong. Recheck your timings. If you think the urines were perfect, call the vendor and check their times and volumes. If times and volumes match and the creatinines do not match you probably have made a mistake and you should get a third as a tiebreaker before going to your physician.


Abnormal means the 24 hour value is known to be associated with risk of stones. Mostly the associations are from prospective observations. Some are based on very firm physical chemistry. The following is directly from the two articles on reading 24 hour urines for calcium or uric acid stone risk.

Write down each of the following that is abnormal – this is your list of abnormalities that are candidates for treatment

Urine Volume below 2 liters per day is abnormal – low flow

Urine calcium above 200 milligrams per day is abnormal – called hypercalciuria

Urine oxalate above 35 mg per day – called hyperoxaluria. (Strictly speaking, values above 25 mg per day are abnormal in that an association with stones can be detected above it. But most people indeed excrete more than 25 mg of oxalate, so a more practical level is above 35 mg per day).  Hyperoxaluria is almost always due to a high diet oxalate intake, low calcium diet intake, or both. Values above 80 mg per day are very unusual and may reflect a systemic disease – your physician will note this – be sure it is discussed.

Urine citrate below 400 mg per day is abnormal – called hypocitraturia.

Urine pH below 5.5 confers a risk of uric acid stones – low urine pH

Urine pH above 6.3 confers a risk of calcium phosphate stones – high urine pH

Urine sodium above 100 mEq per day is above the recommended for US population – high sodium intake

Urine sodium above 65 mEq per day is above the optimal intake for the US population – above optimal sodium intake


Supersaturations are not compared to normal or to stone risk because we lack the critical information. But we know one thing: If you are forming new stones, the supersaturations for the crystals in your stones are too high and need to be lowered.


Here it is, and you are ready.

This is a breakdown of what is already said in another article.



Think about it and make your own decision. When you see your physician, he or she will read your scans with you and count if stones are increasing or decreasing in your kidneys. You will have gathered all your old records and will know when stones have passed or were removed. Your physician may have more such information. Decide if new stones are indeed forming.


We have been here before – most critical to know.


Write them down; these are your relevant supersaturations


This can be confusing so lets review things.

The purpose is to lower by half or more the supersaturations in your urine related to the crystal(s) in your stones. If your stones are mostly calcium oxalate then calcium oxalate supersaturation is your main target. If your stones are mainly calcium phosphate then calcium phosphate supersaturation is your main target.


Correct abnormal urine volume, calcium, oxalate and citrate in that order or priority. For calcium I have linked to idiopathic hypercalciuria, being the usual cause, and that will link to diet sodium and diet sugar as factors your can correct without medications. If your sodium is above optimal (see above) lower it. If you eat lots of sugar, stop. Then, when fluids and diet are both corrected recheck. If CaOx SS has fallen by half or more that may be enough. In principle you could wait and see if stones are now prevented – time will tell.

I am not saying that you treat yourself nor that this is an approach written in stone. I am saying this is a common strategy that your physician may well want to use. There may be reasons not to: You have had too many stones; you have only one kidney; risk to your general health of any more stones is really high.

Thiazide diuretics are a next step when fluids and diet have failed to lower supersaturation enough or new stones form. They should usually not be a first step but rather when follow up 24 hour urines demonstrate that urine supersaturation has not fallen by half or, if it has, if observation shows you that new stones are still forming. Potassium citrate is like thiazide as it will lower urine calcium – not as dramatically – and lower supersaturation by binding calcium, as well as inhibit crystallization. But this agent has become expensive, and is always hard to take because pills are big. So thiazide is a more common first drug.


Correct abnormal urine volume, calcium, pH, and citrate in that order of priority. High volume (above 2.5 liters) is a very useful step here because it can be sufficient in some cases. Calcium is as for calcium oxalate: reduced sodium and sugars, thiazide diuretics is needed when diet and fluids have failed. Urine pH elevation in calcium phosphate stone formers is usually innate and not directly amenable to change but there are odd situations where this is not true. Sometimes people take in very large amounts of fruits – especially smoothies – compared to proteins and have an alkaline diet. One can try rearranging things if you are like this. Potassium citrate is an uncertain treatment here because no trials have been done for calcium phosphate stone formers.


Correct abnormal urine pH and volume in that order of priority. This is the easy one – raise the urine pH, almost always with potassium citrate or other alkali formulationsWhatever uric acid has been forming will form no longer, and some may dissolve.


This is not for you to figure out.

A good screening table is in Five Steps. It requires blood and 24 hour urine measurements and a physician to interpret them. Do not try to figure this one out yourself – it is not wise nor is it practical or safe. Most stone formers do not have such diseases but those who do are in a different realm than the rest. Sites like this one, even though medically rigorous, cannot guide patients with these diseases but only inform them.

The table is not comprehensive nor meant to be. It is a table of highlights. I know many more rare and obscure causes, and so do your physicians.

By all odds you do not have any of the diseases. But do not assume.

Be sure with your physician.

If you have a systemic disease, much of the foregoing will become subsumed in systemic treatments, and these are beyond what we can do here.


Between Five Steps, How to be a Successful Stone Patient, and the articles on reading your reports you are ready to do your best when you see your physician. You should expect to leave with mainly lifestyle and diet changes after a first visit, and plans for a follow up with labs in a month or two. Every cycle is the same, however, until you have reached your supersaturation goals and stones no longer form.

I hope these articles help you achieve what we all want. Let me know. Write a comment. Being only electrons, these articles can be reshaped any time, but it is really patients who can tell me how best to do that.


  1. Angela

    Dr. Coe,
    I am writing today with a lot of frustration. I was diagnosed with a 5mm kidney stone in April that was in my kidney. The ER referred to a urologist. Upon my visit to urologist, I was told it is difficult to pass that size, but given a week to pass it with a prescription of Flomax. In a week, I had not passed the stone and they scheduled me for lipotripsy. Since the surgery, I have felt worse. I went back, they did another ctscan and said it was now a 2mm in my ureter tube near bladder. It is now June and I am really feeling worse. The urologist sent me for a ultrasound yesterday because I still have blood in my urine also. I discovered at the ultrasound the urologist never told me all the ct results because I still have a 5mm in my kidney as well as the 2mm. I have been reading over the last several weeks and found so many recommendations to drink lemon water. I have been doing that very frequently; of course, in hopes of dissolving the stone. Today, I found your site. I have never once had the urologist recommend blood or 24 hour urine test. I do not know what kind of stone I have. I cannot understand why it would be taking this long to pass it and if all my pain and discomfort is actually just from a stone. After reading several of your articles about oxalate, I am now concerned the lemon water may have been adding to my problem. I have been wondering if these stones could be caused from a green smoothie health kick I had been doing for 2 months prior to the first onset of problems. All this being said, I don’t know what to do from here. I do not feel like I am getting anywhere with the current physician. I do not want to do the lipotripsy again. I am open to diet change, but I don’t even know if it is an oxalate stone. Does the physician have to order this 24 hour urine test? Thank you for any information and help!

    • Fredric Coe, MD

      Hi Angela, I am sorry for all your problems. Your physicians are indeed essential but most evaluate and treat stone formers. The article you commented on is indeed a gateway article into stone prevention and links into Five Steps etc. I would begin to use it to plan your evaluation and help your physicians get it done. Please to not go about finding remedies at random, but follow the plan. Here is perhaps a helpful other article that is just getting finished. Your smoothies might have been culprits but frankly those destined for stones are vulnerable to many kinds of stresses other people shrug off. Regards, Fred Coe

  2. Lee

    Dr. Coe,
    When I had a stone last year that required a ureteroscopy (it was stuck in the ureter and was 90% calcium oxalate/10% uric acid), another stone showed up in the CT scan that was 5cm.. I was told it was in the kidney and may stay there indefinitely without causing a problem, unless it grows. Once a stone is already there, is there anything I can do to prevent it from becoming dislodged and traveling down the ureter? If it’s another calcium stone, do they ever get smaller or dissolve on their own or even disappear, or is there anything that can be done to get rid of it, short of a ureteroscopy? It’s like walking around with a loaded gun, never knowing ifor when it’s going to go off… very unnerving. Thanks

    • Lee

      If my post gets read, I meant to say 5mm, not 5cm.

    • Fredric Coe, MD

      Hi Lee, Calcium oxalate stones do not dissolve. The uric acid portion – if the stone has any – will dissolve with increased urine pH. You should have your physicians monitor growth of the stone, and also be wary of pain or bleeding that might signify the stone has obstructed. Whether it is free in the renal pelvis or attached on to the kidney also matters. From here, only generalities, I am afraid; one needs to see the CT scan, and make judgments only your physicians can make. OF real importance, you should have a proper prevention program because more may form. Here is a good introduction. Regards, Fred Coe

  3. irfan bashir

    hi doctor,
    I have been facing kidney stones for the last 20 years. Every ear I have stones of multiple origin expelled by litholapaxy or herbal medicines or ESWL.
    I just did the 24H urine test with abnormal urine citrate of 2.21 mg. with all other tests being clear.
    my age is 40 years now and the urologist advised urocit-k 10mEq b.i.d , which I took for 3 months. After stopping the medication, I again develpoed stone. Please give me your advice.

  4. Lisa Baker

    Oh and I was diagnosed with osteopenia last year with first bone density test….

  5. Lisa Baker

    Thank you for this wonderful resource! I recently passed a 4MM stone left kidney (1st one). The CT from ER visit revealed another 4 MM in left kidney and 4 smaller stones. The analysis of the stone I was told was 95% calcium oxalate.

    A subsequent KUB 2 weeks later as result of miserable back and left side pain revealed only the 4 MM and did not detect other stones. The pain subsided after about a week, but I have no confirmation of passing another stone or the cause of pain. My 24 hour urine results are:
    Urine Calcium 244
    Urine Sodium 171
    Urine Oxalate 34
    Urine Citrate 764
    Urine PH 6.977
    Urine Volume 1.71

    My urologist’s P.A. suggests increase in water, decrease salt and ordered another KUB and urinalysis with C&S if indicated, in 3 months.

    After absorbing information from this site, I’m thinking that I should have another 24 hour urine, perhaps request along with the other 3 month tests. I’m also wondering about the oxalate and PH and if they indicate measures of prevention outside of limiting sodium and increasing volume. Lastly, it was mentioned that 4MM is borderline for lithotripsy. Of course, no one wants to pass a stone but I don’t know much about this procedure and when it makes sense. Your comments are appreciated!

    • Fredric Coe, MD

      Hi Lisa, I gather you have a calcium oxalate stone and your urine values indicate hypercalciuria, high sodium intake, high pH and fair urine volume. I agree with the low sodium, and a good goal is 1500 -2000 mg, lower is better. Likewise, since you have bone disease – your second comment – and hypercalciuria you need 1200 mg of calcium. That high calcium diet will lower your urine oxalate all by itself, and the low sodium intake will keep the urine calcium from rising with the higher calcium intake. Here is an article on that three way approach. The high urine pH is not of obvious cause, but the stone is CaOx not calcium phosphate so leave this alone right now. By all means get a follow up 24 hour urine and be sure the sodium is down, the oxalate is down, the volume is up and the urine calcium is no higher. Regards, Fred Coe

  6. Frank

    I had a first calcium oxalate stone 4 years ago. Then another one that got removed through surgery in October.
    Both stones were about 6 mm big.
    I just did the 24H urine test.
    ” Only” the following results are outside the recommended ranges:
    – citrate: 160 mg
    – magnesium: 44 mg
    – potassium: 17.
    I have been adding a small spoon of pure lemon juice into each glass of water that I drink, and I drink 6 to 10 large glass of water per day.
    What treatment would you recommend to prevent recurrence ?

  7. Adam

    Hello, I was just wondering if you could either clarify for me or break down the options a little bit more. I have had 3 kidney stones. The last stone was calcium oxalate. My serum calcium number is 9.6. My Urine Citrate 249mg per day. My urine calcium 351 mg per day. You mention “Correct abnormal urine volume, calcium, oxalate and citrate in that order or priority”. Urine volume seems obvious to fix, increase water intake. How ever correcting abnormal levels of calcium, not as obvious for me. oxalates I would assume could be corrected with diet modification. Then finally citrate I am guessing also would be diet based like lemonade, and potassium citrate supplements. Any further you can help me understand different options to correcting those areas would be appreciated. Thanks for your time,


    • Fredric Coe, MD

      Hi Adam, Thanks for the question. So, you have your crystals – calcium oxalate, and you have your abnormalities: citrate calcium and although I do not see a volume presumably that as well. You correctly note that fixing volume is simple enough – though burdensome in reality. Remember the goal is to lower the urine supersaturation with respect to the crystals, which for calcium oxalate means that supersaturation. You do not mention an abnormal urine oxalate, so I guess that is not present.

      The text reads: ‘Correct abnormal urine volume, calcium, oxalate and citrate in that order or priority. For calcium I have linked to idiopathic hypercalciuria, being the usual cause, and that will link to sodium and sugar as factors. Thiazide diuretics are a next step when fluids and diet have failed. They should not be a first step but rather when follow up 24 hour urines demonstrate that urine supersaturation has not fallen by half or, if it has, if observation shows you that new stones are still forming.’ So with water I would lower urine sodium and diet sugar and see if urine supersaturation has fallen by half. If so, and if stones are not highly frequent, I often wait to see if that is enough. If not, then thiazide.

      Also, I did not mean you are to be all by yourself. Your physician can certainly help a lot. But the intent of the article is to prepare patients to get the most out of the physicians who care for them.

      Your question is so important I have edited the article to make these points clearer than they are now. Much thanks, Fred

    • GULREZ KHAN ("Gus")

      Hello doc,

      I live in Texas. I am a 36 years old male. I am 5.7 tall and weigh 150 pounds. I mean, I am in a great shape. However, 2 weeks ago I passed a calcium kidney stone. My PCP told me to check online about the dietary recommendations after having a calcium kidney stone. Believe me, the research for a near perfect diet for this is more frustrating than having a kidney stone. Every sources tells a completely different story. I am tired of researching due to varying perspective.

      So, you tell me what do I eat and drink and what not? I am exhausted of looking at oxalate, low oxalate , high oxalate, and all this crap.


      • Fredric Coe, MD

        Hi Gus, You are reading the article I wrote about what to do. It does not really make much of oxalate but rather that you need to know why the stones form in order to prevent them. First, what is the stone? Calcium goes with another name like oxalate or phosphate and that matters. Second has your physician looked for and excluded systemic diseases as a cause? Third, you need 24 hour urine testing: WHat is causing stones of the kind you formed? There are no varying perspectives about what I just wrote: Every responsible physician will agree these three steps are needed. Once you know what is wrong diet or even meds can be figured out. Without these basics, no one can tell you what will work. In general, assuming you have the common calcium oxalate stone and no systemic diseases, the ideal kidney stone diet is more or less the modern ideal US diet; take a look. Regards, Fred Coe

  8. Ed Smith

    Hi, what is the oxalate content of lentils?

    • jharris

      Hi Ed.

      Don’t have a known source, but from all my readings, I think they tend to run on the higher side. I would have them in small portions.


  9. Tonya Blaine

    i have had 2 kidney stone surgeries in 2 yrs…. I had a 24 hr urine done with the following results;
    are these results normal

    • Fredric Coe, MD

      Hi Tonya, I guess there is not enough information to say. What were the stones made of? For example were their crystals calcium oxalate, or calcium phosphate, or uric acid or some mixture. Was the urine collected representative of your normal life as was led when you formed stones? Let me know and I will try to help. There is no such thing as a normal supersaturation value, it is that the supersaturation in the urine of someone who is forming new stones is too high in relation to the crystals in the stones formed. Take a look at this video. Regards, Fred Coe

  10. Michelle Groleu

    Is it common to have so many stones that they cannot be counted? Thanks!

  11. Andrea

    Thank you very much for this very clear articles about kidney stones. I have followed many of the steps you mention and I will make the story short. I have medullary sponge kindey (only one) and in this one I have stones since my early twenties (not sure why they didn’t appear before my 21st year of age, may be due to me starting on levothiroxine at 18?). I have been on diuretic and allopurinol for 10 years and things were quite smooth until I moved to UK where doctors recommend me to stop taking this medicine. The following 5 years without any regime (only drinking lots of water) made me go through 9 surgeries of different types. I got tired and i consulted specialists in other countries and they put me back into my previous treatment of diuretic and allopurinol, they found i still have Hypercalciuria and Hyperuricosuria. Now my stones have been tested and they are 80% calcium phosphate and 20% struvite. I don’t understand how this is possible as my urine is always very acidic, it has been all my life. They also recommend me to take potassium citrate but I am afraid as it is no good in cases of infections, and I have a couple of infections during the year. So I decided to drink lots of lemonade (homemade) and keep my regime of low purines, low salt, low sugar. I have received so many different views from doctors that I do no trust completely in them anymore.

    • Fredric Coe, MD

      Hi Andrea, I wonder if most or all of your stones are coming from the one kidney with diagnosed MSK. If so, the urine from that kidney might be very alkaline whereas that from the other kidney acidic so the bladder urine average is out of step with the conditions where stones form. The struvite is a concern as it means some stone material is being produced by bacteria themselves, although I must caution that it is detection of struvite that analysis labs most often fail. Let me know if my guess is correct. Regards, Fred Coe

      • Andrea

        Hi Doctor Coe, thank you very much for your reply. I went through some difficult times since I left my question here so I am sorry I completely forgot about checking this website. I re-discovered it days ago and I have to thank you and your colleagues for the vital and useful information that it contains. I liked most the info about MKS, some of it was completely new to me. I have been stone free from left kidney until very recently, when some small stones have been found in it too. All my problems (staghorn calculi, surgeries) have come from my right kidney, diagnosed with MSK. I don’t know if I have dRTA too but I am suspecting it. I said that my urines are normally acidic, but I didn’t clarify that urine checks collected in the morning are usually neutral or acidic, but 24 hs urine tests were all more alkali: 6.77, 6.5, 6.50. I had two stone analyses done and the result was apatite 80% and struvite 20%. Since I re-started my drug treatment with idroclorotiazide 25 mg, clorhidrato amiloride 2.5 mg and allopurinol 100mg per day (middle 2015, recommended by doctors in my country, not in UK) I have had no serious infection in my kidneys and apparently not too much stone grow. But my physician in UK says my calcium and uric acid tests in 24 hs urine comes normal (when done in my country they never come normal, which makes me think about which normal range do they work with here. In Argentina, where I am from, the top normal level is 220 for calcium, while you, on this website, say that the top limit is 200, which makes complete sense to me). So my doctor here (UK) recommended me to take potassium citrate instead of my other drug treatment (or at the same time) and I am concern about its effectiveness in my case. Also, in two occasions, when my vit. D and PTH were tested, they came a bit abnormal. My vit D was low (6.20nG in 2011, and 15.10nG December 2016) and my PTH a bit high (62.9pG in 2011 and 58.9 December 2016). Some doctors in my country recommended me to take vit D supplements, but I am afraid of causing more damage to my delicate calcium excretion balance, so I haven’t taken them yet. My serum calcium (and other serum minerals) has always been normal, but not my calcium in urine. My concerns are as follows: Should I make my urine more alkali? Should I take potassium citrate? Should I be concern about my PTH and vit D levels? Unfortunately, I have had mixed answered to this, which have made me more confused. I have all details registered in a file as you recommend in your website and I could send it to you if you think you need to know more. I wish I had someone like you or your colleagues to see near where I live. Thank you very much for whatever you could tell me and I apologise for my long comment.

        • Fredric Coe, MD

          Hi Andrea, Your stones are the most important matter. They are apatite – calcium phosphate – no doubt because of the alkaline urine and high urine calcium, and struvite which is formed only by urea splitting bacteria – infection. This latter can be an artifact in that struvite crystals are often mis interpreted in stone analysis labs, so I would not be certain unless multiple stones contained it. Treatment is best with low sodium – 1500 mg diet, high calcium 1,200 diet, and the chlorthalidine. Potassium citrate is not ideal. The low sodium is essential for the thiazide to be most effective. Amiloride helps prevent potassium loss. If you are indeed vitamin D deficient I agree with your physicians it should be treated. IN fact given your treatment above I seem to agree with your physicians. ALlopurinol is irrelevant to you and so is urine uric acid given your stone analysis. Being a professor I am always ready to donate my services where possible. If you wish to send me your reports: I will be pleased to read them for you so long as it is clear I am not really in a position to interpret them in the context of your entire medical condition. Regards, Fred Coe

          • Andrea

            Thank you very much for your reply! The lab analysis of my stones were first done in 2013 after they broke down my huge staghorn calculi during a surgery. This calculi grew quickly probably due to several infections that were diagnosed too late or not diagnosed properly on time (sometimes I do not have fever even having an infection). Doctors told me at that time that the stones were made of struvite and calcium phosphate but I do not have this result with me so I don’t know the percentages. The second lab analysis I made it after I passed a stone in 2015. I took it to Buenos Aires to be analysed. This is the only one I have with me, that says 80% apatite and 20% struvite, after which doctors there put me on a drug treatment with thiazide. I tended to have many infections in the past but since I am on thiazide I noticed that I have a lot less infections. Since you agree with my treatment I am much relieved now. This treatment has been recommended to me by specialists in Buenos Aires. Here in UK they think I don’t need the thiazide drug, but I much disagree because I believe I need it. I have been reading all I can from pudmed and other sources, books too, because I want to know as much as I can about my condition. I have been always in doubt if to higher my ph or not and I have received different opinions from the specialists. One said NO to potassium citrate, the other here in UK said YES. Imagine my confussion! I will try to follow a healthy diet lowering as much possible sodium and sugars too, more than until today, and see if I am better. I am afraid of infections so I think I will not try to make my urine more alkaline, although it is a pity as I love fruit juices!. Thank you very much again for your amazing website and for answering my questions! Best regards, Andrea

            • Fredric Coe, MD

              Hi Andrea, The struvite certainly is from infection and has appeared in several stones therefore making one believe the analyses. I am glad the thiazide is helping and advise you keep diet sodium as low as possible to make the drug more effective and reduce potassium loss. Regards, Fred Coe

              • Andrea

                Hi Dr. Coe, thank you very much for answering our doubts. People like me with stones have many questions and sometimes we do not find the answers, or the answers are not convincing or they recommend the exact opposite. I value your opinion a lot. I have never found before such a complete website with excellent information for patients, one that wants to inform but also educate. Well, my questions are as follows: without forgetting your previous recommendations, I wonder if 1. Switching to Chlorthalidone will be more successful at keeping my loss of calcium at a normal range? I used it in my twenties and I remember taking it once a day. Now taking a pill twice a day is not easy, sometimes I forget second dose. In addition, taking the second half at 8pm makes me go to the toilet many times during the night. 2. Is there any (simple? inexpensive?) test to diagnose if I really have incomplete dRTA? 3. Sometimes I see that my PH stays high during the day (instead of being around 8 only in the morning and going down to 6-5 later). Two or three days in a row persistently at 7.5-8ph worries me a lot (as average of both kidneys I wonder how high must be in the one with MSK). Does it help lowering the PH drinking cranberry juice or taking ascorbic acid? Or better stop taking my allopurinol pill? Sometimes the strips comes with positive “trace” of lymphocytes and/or trace of blood (no symptoms at all except a very mild pain); 4. Should I also be concern about oxalate as other stone formers are? I have never had a stone of oxalate, but I have always being told to avoid the food that contains it, and very specially, vitamin C (that actually helped me a lot in my younger years to be cold & eczema free). And finally, as I have read that a high dosis of Vit. D can be harmful, such as 100,00 UI every three months, at the end of the day, if I take a lower dose, let’s say 1,000UI a day, after 3 months I would have taken 90,000UI after all. Is it the same to take small amounts every day or one high dosis every 3 months?.(or until my vit D goes back to normal). I know this is a long post and I apologise for this. They are specific questions that have been in my mind for too long! Many thanks in advance!

              • Fredric Coe, MD

                Hi ANdrea, Chlorthalidone is indeed more convenient. The best dose is low – 12.5 mg or 1/2 of a standard 25 mg pill. Keep the urine sodium very low to avoid potassium loss. One cannot lower urine pH safely, and I do not care if you have RTA so long as your blood CO2 content – standard blood panels have this – is normal. Allopurinol is irrelevant and should not be expected to help at all. Oxalate is not relevant to your stones. Vitamin D is used up, so 1000 or 2000 units a day is a way to keep your blood levels normal. Regards, Fred Coe

  12. Carl Colson

    Any doctors in the Seattle area that you would recommend?

  13. Carl Colson

    Excellent information – is there a doctor you would recommend in the Seattle area.

    • Fredric Coe, MD

      Hi Carl, I do not mention physician choices on this site – apart from a few special exceptions but we have communicated by private email. Regards, Fred Coe

  14. Sharon

    Dear Dr. Coe,
    Can you recommend a good nephrologist for my son to consult with in LA. He is covered under the Kaiser system there and has had two stones removed in the last two years. They were too large to pass and caught in his ureter.
    Your website is very helpful, thank you for putting all of this information out there so patients can understand their issues better.

  15. Marilyn

    Hi Dr. Coe,

    I am a dietitian and I am trying to wrap my mind around all the dietary implications when you have a Litholink report. I have found this website to be a WEALTH of information in helping me understand. Many thanks to you and your colleagues.

    From a dietary standpoint, do you limit oxalate when the SS CaOx is elevated and/or when Oxalate 24 is elevated?

    Also, if I am understanding correctly (in reference to CaOx stones), there really isn’t a reason to limit calcium in the diet and if they are not getting enough, it may be prudent to add a 1,000 mg (500 BID) supplement daily? At first, I was getting thrown off by the Litholink report of high urine calcium, but that may result from calcium loss from the bone and indicate that they need more calcium to help replace bone loss and bind with oxalate? Sometimes I see Litholink reports that advise reducing calcium and so I am becoming confused.

    Is low sodium diet recommended only when 24 hr Na is high on the Litholink report, or does this go hand in hand with recommendations for CaOx stones?

    Again, thank you to you and your associates for this great work. It still goes over my head at times, but I have found it to be very useful!


    • Fredric Coe, MD

      Hi Marilyn, Oxalate intake matters when urine oxalate is high, otherwise no. Low calcium diet has no place in stone prevention, and will increase absorption of food oxalate. The amounts you mention are accurate. Food calcium sources can go a long way. We are writing an article on how to get high calcium low sodium foods – not easy. As for hypercalciuria, it is at heart a disorder of renal calcium – sodium balance. As diet sodium rises – marked by urine sodium – urine calcium rises in everybody. Idiopathic hpercalciuria arises from an abnormally high slope of calcium increase per unit of sodium increase. SO lowering diet sodium will bring most hypercalciurics into the normal range. Values of 1500 mg diet sodium are ideal. For bone, in the one reliable bone balance study that addresses the matter, bone mineral gain could be achieved only with high calcium combined with low sodium. Hypercalciuria is central to calcium oxalate and the two calcium phosphate stone formers: hydroxyapatite and brushite. So it is a general problem with all calcium stone formers who are idiopathic – no systemic disease as a cause. I hope this helps, and thank you for the excellent questions, Fred Coe

    • Jill

      Hi Marilyn-

      I would have many nutritionists ask me to consult them when they got a LL report. If I can ever help, please let me know. Would be a pleasure.

      You can email me at jharris1019@gmail.com and can set it up!

      Very best,


  16. Steven

    This is such an excellent resource. Thank you so much. I am only recently suffering with stones and this information is vital to me. Great work!

  17. Carla

    Hi Dr. Coe,
    I am getting ready to do two 24 hour collections, with a follow-up through Litholink after I change my diet (lowering oxalates, sodium, sugars, and animal protein, plus consistent increased fluids). My new nephrologist ordered this at my request after I explained your protocol to him. My question is – How long should I wait after the 48 hr. urine test to do the follow-up? I want to give the dietary/fluid changes time to see if there is a obvious change in my numbers. My doctor didn’t know, so I asked Litholink and they said a month or longer.
    Thank you,

    • jharris

      Hi Carla,

      Ideally we want you to wait 4-6 weeks as the dietary effects are crucial in your results. This amount of time ensures that.


  18. Ernie

    Dr. Coe, i was a patient of yours and would like to follow up with you regarding my status. Can you please email to follow up with you. Thanks.

  19. Gayle Creasman

    Having been plagued with large stones one 14mm one 12mm and a few small ones for over a year and having gone through 4 laser surgeries, one lithotripsy, multiple stents which I currently have two of, I stumbled upon your website as I am searching for better answers and treatment than I am currently receiving. I knew that there had to be a way to at least slow down the development of these stones. I will say that it is a lot of information to take in and I have a followup appointment to see my urologist on Wednesday to hopefully remove the stents and find out what he feels would be the next step. My question is would I be better trying to find a nephrologist that specializes in stone treatment ( I have not found anyone in the Charlotte, NC area) or should I go to a larger university. In all this time, I have never done a 24 hour urine test. He said he had some ideas that might work I however would like to at least have more optimism than might work. Your site has been very helpful, but with underlining medical conditions I need more than just the website. I have started increasing my fluid intake and checking on foods that I should avoid.

    Any information on someone in the area or if I need to travel there would be helpful.


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