24-Hour Urine Collections: Why and How

Jill jpegWhy

You have a kidney stone episode and your doctor asks you to collect your urine for 24 hours. Why oh why is this being asked of you? Isn’t it dreadful enough that you just had a kidney stone?

The only way to find out WHY you are forming kidney stones is to complete a urine collection.

The test results will tell your doctor how saturated your urine is with stone making crystals.

The more saturated your urine is, the more likely you are to form new stones.

Some clients have come to me and said, “Why do I need to do a urine collection if the doctor removed my stone and had it analyzed?”

A stone analysis may tell you what type of stone you made, but there are many different reasons you may have made that type of stone.

Figuring out your prevention plan is very complicated, and without a urine collection it is nearly impossible.

Figuring out all of the details behind urine collections can be exhausting. I just released a course called The Kidney Stone Prevention Course to help you understand how to implement your physician’s prescribed treatment plans.


One Day or Two Day Collections?

When you do your first collections, the ones your treatment is going to be based on, it is wise to do two: Two 24 hour urine collections.

Before you start pulling your hair out, let me tell you why.

What you eat and drink during your collection is going to be represented by your test results. If you do your collection on your birthday, you may be celebrating, drinking, eating foods you don’t usually eat and this will not represent a “normal” day for you.

If you do two collections, your test results will show a better picture of what you are eating and drinking.

Sometimes I see a two day collection and the day to day results are so very different they enable me to ask some important questions. For example, “The sodium levels in your urine were very high on your first collection, did you go out to eat that day?”

When I worked at Litholink Corporation we would tell patients to collect their urine on a weekday and a weekend day.

We requested the collection be completed this way because typically what we eat during the week is not what we eat during the weekend.

This way the lab results would show the difference between eating and drinking habits and we could offer better treatment suggestions to the doctors on the lab report.


Always Drink and Eat Normally

Many patients don’t want to hear their doctor scold them for not drinking enough so when they do their urine collection they drink and drink and drink. This is not what they usually do. Some already know they were eating badly and made some big changes so their tests would look better.

Why am I going to call you out on this? Am I just a pain in the neck?


Cheating on Your Collection Days Will Not Help

If you drink more than you usually do or eat differently than you usually do, your doctor will base your treatment plan on what you did for those days.

You want your treatment plan to be based on what you usually did when you formed stones so that changes you make will lessen your chances of making more stones.

Suppose you already know you should drink more water, and you do it during your collections. You never did it before, when your stones were forming. Your doctor sees that you’re drinking 4 liters of water a day (you wanted to impress him or her).

S/he will be impressed and assume that low fluids were not and will not be your problem.

But, maybe low fluids were your problem. You won’t know and neither will your doctor.

So what?

No one, including you, will make fluids a priority and you may well forget to keep showing off.

Then what?

Maybe nothing else was wrong except low fluids, and that was gone for the moment – when you did the tests.

Maybe the fluids have already fallen back to your original low levels.

Your doctor will not be able to offer you any help, or worse, may tell you something generic like “avoid all green, leafy vegetables”. I don’t want anyone avoiding green, leafy, veggies if they don’t have to.

I tell clients, “if you drink gin all day then please do that during the test”.

If you don’t drink much water, please do as you normally do.

Getting on the right treatment plan is imperative in preventing new stones from forming. The only way to get on the right treatment plan is to eat and drink as you normally do on the days you are collecting your urine.


Diet Changes Before Collection Begins

Some of you were told to change your diets before doing the urine collection and wind up doing the collection while on your new diet.

This will NOT help.

You want your results to show what you did while you were making stones. For the day(s) you are asked to collect your urine, eat as you did before you knew you had a kidney stone.

Then go back to doing what your doctor told you to do or what s/he tells you to do after the test results are available.

Don’t Collect During Holidays

Many people will want to do their collection on the holiday because they are off work. If you are like me, you eat differently on holidays than you do on non-holidays.

Thanksgiving is not representative of how you normally eat, so this is not the time to do your collection.

Remember, since your results will show what you ate for that particular day, a treatment plan based on holidays will not be useful to you. Your doctor may tell you to go on certain diets that you do NOT have to go on.

That would not be helpful at all!

Make Time to do the Urine Collections

I completely understand that doing a urine collection is a total pain in the neck. It is annoying and nothing you want to do.


There is nothing quite as bad as having a stone attack. If you have to weigh one against the other, doing a urine collection is the clear winner.

Find the time. It’s worth it.

Occupation Need Not be a Barrier

I have had pilots, truck drivers, surgeons, salespeople, and teachers all find the time and make collections while at work. Whether or not it is possible depends on a lot of circumstances, but doing it on the job is the ideal for one of your two days.

Some of you will not be able to bring the collection jug to work.

Perhaps you might have to take a day off from work.

If you do take a day off from work, please drink and eat as you normally would on a work day.

If you do a two-day collection, remember to do one on a weekend so your doctor can see how it differs from a weekday.

Questions About Your Collection

Once you receive your urine collection, please read all instructions on how to complete it.

If you have any questions, call the place of business you received your supplies from and ask them all the questions you may have before starting the collection.

It is dreadful when you have to re-do a collection because you didn’t do it the way they wanted you to.

Follow-up Collections

Once you do your initial 48-hour urine collection, the doctor will go over the results with you.

From those results, you will be told to do certain things that will help prevent stones in the future. You may be told to go on medications, drink more water, change your diet, or all three.

Four to six weeks after you have incorporated all the changes your doctor has prescribed for you, your doctor SHOULD ask you to do a 24-hour urine collection to make sure those changes are working for you.

If you don’t do a follow-up, how will you know if your treatment plan is working?

If your doctor doesn’t order a follow-up, ask for it.

You should expect your doctor will contact you about your results and make whatever changes are needed to get you the best possible prevention.

Annual 24-Hour Collections

Our urine chemistries change over time. It is prudent that you complete a yearly collection to ensure your treatment plan is still working for you.

Partly urine chemistries change because we are getting older, or have developed some new disease condition.

Diets change even if we are unaware of the changes because they occur slowly.

We gain or lose weight which can affect urine chemistries.

Our habits change: We give up or get a health club membership, or start running.

A Final Thought from Jill

Clearly now, you can see how important it is to complete urine collections.

I want you to know that I don’t ask you to see the importance of doing these darn collections without having compassion and empathy that you have to do them.

I know they are not convenient, nor are they fun.

Just keep in mind that if you don’t complete a urine collection, you will not know why you formed stones and will most likely keep right on forming them.  I want to keep you away from that scenario.

Prevention is always our best defense. Completing your collections is a pretty benign way to keep stones at bay.

Return to Walking Tour about Supersaturation

Figuring out all of the details behind urine collections can be exhausting. I just released a course called The Kidney Stone Prevention Course to help you understand how to implement your physician’s prescribed treatment plans.


57 Responses to “24-Hour Urine Collections: Why and How”

  1. Kearstin

    Hello I’m an 18 year old female, I’ve recently went to my urologist with 6 stones in the right kidney and 5 in the left. I’ve had kidney stones since I was 13. My urologist did a comprehensive metabolic panel and PTH test and that all came back normal but I have to do a 24 hour urine test. What would be shown in the urine that wouldn’t be in the blood? Thanks

  2. Don

    Hello. ..
    I’m suffering of uti on and off for 8 months if not mistaken…. drinking water, antibiotics didn’t di much work. … a couple of doctors discovered I have deposits mostly on right kidney by ultrasound. .. and I think the right ureter is inflamed but I don’t know since it hurts often in one point above ovary it might be a stone. . it’s frustrating to live in pain with not much of offering a solution (drink water take a few pills and you’ll be fine. … not really my reality)
    anyway I’m going to do a few tests and this 24 urine test as I read will help with my condition. .. so please can you help in my case what elements need to be checked such as calcuim uric acid etc

  3. kim

    I’m doing the 24 hour pee test if I have cancer or a stone will they find it. I’am a smoker that’s the only bad thing I do besides drink coffee and tea. there telling me not to have anything like that while i’m doing my test so will smoking screw up my test.

    • Fredric Coe, MD

      Hi Kim, urine testing will not identify cancer unless it involves special cytology. Smoking is not an issue. Cancer is detected with other means than 24 hour urine collections. Regards, Fred Coe

  4. Maria

    Hi Im doing a 24 hour urine collection (catecholamines, metanephines, vma, hva and 5hiaa) but i drank diet coke, can i still collect my urine?

  5. Kara

    So I started my one day collection the night before on accident… Will this affect my results?

    • jharris

      Hi Kara,

      You must collect for a 24 hour period. When you start that 24 hour period is up to you.

      Hope this helps-


  6. Reese

    I have a 24 hour urine that starts in the morning. Is it best to not have any alcohol, like wine before the test?

    • Fredric Coe, MD

      Hi Reese, It is best to do what you usually do so the sample will represent your real life. regards, Fred Coe

    • jharris


      If you normally drink alcohol, then it is fine. If this is something you don’t usually do then save it for after the test. You want to see what a normal eating and drinking day looks like on your report.


  7. Nihal


    When you are doing a 24 hour urine collection, does the urine need to be refrigerated during the collection period and/ or after the collection period, before it is returned to the lab?

    If no refrigeration is required, how much time can the urine be kept outside, before returning it to the lab?


    • jharris

      Hi Nihal,

      You must ask the company who you got it from and they will tell you. If this is from Litholink, you do NOT refrigerate it. Don’t worry about it being outside. It is fine.

      Best, Jill

  8. anon

    What happens if I get my period while doing the collection? Can I still collect the urine?

  9. M. Dink

    I take Urocit K. My doc said that taking it during my urine test will not affect my results, is it okay to take Urocit while do ing the 24 hour test? Or, will taking any of my vitamins Vitamin D3, Prenatal, probiotic, krill oil, and sometimes Biotin affect the results?

    What if for the past three weeks I’ve completely changed my diet for the better. Do I need to go back to my old ways for 24 hours when I’m planning on sticking to my new healthy eating habits?

    Thank you!

    • Fredric Coe, MD

      Hi Mandy, The purpose of the test seems to be follow up to see how well your treatment is going. So do your new diet and your medication for the test. As for the other stuff, if you use it all the time, use it for your tests, too. Regards, Fred Coe

  10. Kris

    I had a hysterectomy 5 years ago for early stage node negative breast cancer. I am 49. I currently take Arimidex. My prognosis was 4% risk of recurrence. Since my surgery (not before) my calcium lives at 9.7-10.2. My Albumin lives at 4.7-5.0. Four years ago a routine CT Scan showed two stones. I have them followed annually by ultrasound. This month, my doctor decided to do a 24 Urine as the stone grew a little. My 24 urine was 452, which I understand is elevated. My question with this test is how high is 452? Another question is does lack of estrogen raise urine in calcium and affect urine results?

    • Fredric Coe, MD

      Hi Kris, Indeed a urine calcium of 452 mg is very high, enough to cause calcium stones. Lack of estrogen can raise urine calcium because bone mineral is lost easily and perhaps because of changes in kidney tubule cell calcium conservation. You should take steps to lower the urine calcium and protect your bones. At least, very low sodium diet and high calcium diet together would be helpful. Possibly a thiazide medication in addition – not instead of. This is pretty complex because of your estrogen status so take my comments as something perhaps your physicians might want to consider. They may want to use a bone oriented drug, as well. Regards, Fred Coe

  11. james g

    How high is too high? Just got a result from 24 hr urine calcium of 1,665 mg/(24.h). Tested due to hyperparathyroidism. Should I be concerned?

    • Fredric Coe, MD

      Hi James, That is indeed so high as to make one think about errors. I presume you have primary hyperparathyroidism, from your comment, and that your physicians plan to cure it surgically. After such a cure be sure to check again that the urine calcium has fallen to a more normal value. As for concern, PHPT is best cured sooner than later and in your case sooner. But your physicians know this. Regards, Fred Coe

  12. Jessica

    Any ideas why I would have chronic recurring calcium phosphate stones (5-10mm size), when my 24 hour urine collection results just came back as normal? None of my levels are elevated. I’ve had 6 ESL surgeries, plus a laser / needed stent surgery. Not a soda drinker, no family history. Stumped. Thanks,

    • Fredric Coe, MD

      Hi Jessica, Calcium phosphate stones can be a real problem. I doubt your results are uninformative; so called normal limits are not so easy to set for 24 hour urines. Take a look at this article on how to read your results and see if there are clues. Be sure your blood tests are all normal – especially serum calcium. Worst case, if you want to put up your results I could look. Regards, Fred Coe

  13. Lauren

    I have both calcium oxylate and Uris acid stones. My urologist has not ordered a 24 hour urine test. After talking to 2 urologists in the emergency room they were very surprised by this I am requesting one as soon as possble. I had a 1.2 cm kidney stone removed by lithotripsy and a 9mm removed at the same time I seem to be growing them rapidly. Am I correct in requesting the 24 hour urine test ?

    • jharris

      Hi Lauren,

      Let me put it this way. If you came into the er with pains in your stomach wouldn’t they want to do some testing to see what the problem was? Same for stones. If you have them you need to figure out why. And for goodness sake why would you wait for anymore stones to occur before doing the test? Let’s prevent them before that happens. The only way to start prevention is to see why. The urine collection will do just that. Good for you for asking for it!

      Do it!


  14. Chana

    Question: I need to do the 24 hour urine collection. However, I stop taking my cholestrol medication – I read that one of its side effects is kidney stones. I’ve never had kidney stones in my entire life ( 52years) the only thing different is the cholestrol medication my doctor perscribed- livalo I’ve been on it for 7 months. Should I start taking it again then do the urine collection. I stopped the medication for about a month now. My stone was removed two months ago. I just wasnt sure if the urine test would show that it is the medication that is causing my stone or not.
    Any information you can share would be helpful. I just don’t want anymore kidney stones.

    • Fredric Coe, MD

      Hi Chana, I know of no reason your urine testing requires you stop your statin. But if you did stop go ahead and test. I have not as yet encountered statins as a cause of stones but am always glad to learn. Regards, Fred Coe

  15. Reece

    Can you drink alcohol while testing? At least on one of the days.

    • Fredric Coe, MD

      HI Reece, It is not ideal to do so above your usual. If you drink a certain amount every day, just keep things that way. But do not drink on your collection days more than you usually would. The purpose of testing is to get a sense of your usual behavior. Regards, Fred Coe

  16. Abby E

    I’m hoping that the urine testing in doing this weekend will help me prevent the gigantic stones I seem to form! Most recent was over 35mm sitting atop a bed of gravel and is the second one I’ve had of similar size in less than 10 years.

    Having to go through having a nephrostomy and PCNL is no fun 🙁

    • Fredric Coe, MD

      Hi Abby, Be sure those stones passed or removed are analysed so you know what they are. And it is time to be sure you are getting the kind of prevention to prevent more such in the future. Here are a few good places to check. Regards, Fred Coe

      • Abby E

        Thanks Dr Coe. Most recent analysis showed 90% something apatite I think, but previous stones were mostly calcium oxylate so I have been on a prevention plan for many years. A small stone in my left kidney (showed about 6 months after a PCNL in 2008) was stable in the upper pole for 2 years so I was instructed see the urologist on an as needed basis. I had no symptoms until a few months ago and by the time it was discovered, it was a chore getting it out of there!

        Hoping the 24hr study gives some insight! Thanks again!

        • Fredric Coe, MD

          Hi Abby, The analysis means you are forming calcium phosphate stones as well as calcium oxalate stones, a not rare outcome. Usually this conversion to CaP comes with time, sometimes shock wave treatments. Your physician should take a very close look at your urine chemistries and be sure that both the calcium oxalate and calcium phosphate supersaturations are very low. Regards, Fred Coe

  17. LH

    I have a 3-4mm stone which a CT confirmed. I then had a follow up 3 months later with an X-ray and an ultrasound, but neither showed that the stone was still there. I had no symptoms during this 3-4 month time period, but then a few days ago I had the immense pain from the kidney stone.

    After the Ultrasound came back negative they wanted to do a bloodtest and urine collection. Is that still necessary since the stone is still inside me?

    • Fredric Coe, MD

      Hi LH, I would do whatever your physicians say as it is unclear where that stone is and what it is doing. The x ray and ultrasound may not be able to visualize the stone, it may be there. Your physicians need to manage this. Good luck, Regards, Fred Coe

  18. Sandra

    I had passed a stone 3 weeks ago and still have one more in my kidney. Not moving yet.
    I will have check up again in 6 months w/doctor but mean while i’m supposed to do 48 hr collection. They told me it takes 3 months for them to do test and get results. So I can do my collection in the next 3 months any time is convinient as it will not make the diferance in results while they advised me to drink more water and have some general changes in eating. By reading your article (which makes a lot of sence) i see it is oposite of what the doctor gave me as instructions. (?) Should i do collections now before new changes take effect (it would make sence)? Is it realy possible that testing and gettingbresults takes 3 months and how are they storing it for such a long time? If they already have found another stone in my kidney, why is my check up so far in 6 months? Is it dangerous, i mean the stone can move any time from now on? Oh, the pain 🙁

    • jharris

      Hi Sandra,

      Sorry to hear about your stone trouble. They are a nasty beast the reason we are so committed to this website and to prevention in general. No it doesn’t take 3 months. If you are doing a Litholink test (or any 24/48 hour urine collection), it will take a few days to have the labs run and completed once they receive your specimens. Could be the doc meant that it will take 3 months for you to get and appt and see him/her.

      It is best to do the collection (if this is the first one you have ever done) and eat and drink as you normally would. This way you can see how your eating and drinking habits before you got the stone may have caused it. Also important is to do the collection when you are feeling ok. If you are in pain then you will not be eating and drinking normally.

      If the other stone is in a secure place and is not moving the doc may say come back in 6 months and see where you and your stone stand. Has it moved? Has it grown? He/she will mostly likely order a scan so that they can keep an eye on it. I would do the collection soon, when you feel up to it. How did they give you prevention when you have not done a collection. That is the reason to do the urine collection. Until then, we don’t know why your are forming stones and changing your diet may or may not help. Don’t know for sure.

      It is always a good idea to increase fluid intake. So that is fine, but anything else should wait until results are in and final. If you do drink lots more water during the collection be sure to tell doc that those values represent an increase in water intake since you last talked.

      Hope this helps.


  19. Sarah Sep

    What exactly are they screening for in a 24hr urine analysis?

  20. shaik zubair

    hi jill are there any medicines that lower down my creatine levels please suggest some medicine that i should take or just water.

    • Fredric Coe, MD

      Hi Shaik, If you mean your serum creatinine, which is a measure of your kidney function, the question is very complex. Water is not an option. Reduced kidney function is a serious problem, and medication use likewise. Is it in fact your serum creatinine level you are speaking about? PLease let me know and I will try to be helpful. I suspect from the chain of questions that you are referring to your urine creatinine and I have answered that question. Regards, Fred Coe

  21. shaik zubair

    jiill please answer my question i have a lot of questions and tension also.

  22. shaik zubair

    greetings, jill i am shaik i have an operation last 14 april 2014, and now i am having a creatine level of 1.5 in my urine i am not taking any medicine and is only drinking 3 ltrs of water daily in 24 hours is it enough of should increase the quantity.please advice.

    • Fredric Coe, MD

      Hi Shaik, Your question is puzzling. If you mean the amount of creatinine in your urine, and the 1.5 refers to amount per day, the amount of urine creatinine reflects your muscle mass. Your muscles produce a fixed amount of creatinine per minute, and in a full 24 hour collection you will have the same amount each day. The measurement is intended to be sure of completeness of the collection and that is the reason it is made. The materials in your urine that affect stones are such as calcium, oxalate, citrate, pH, urine volume itself, and others, but not creatinine, YOur physician is the one who needs to interpret these measurements for you and plan a proper treatment. Regards, Fred Coe

      • Tina

        I’ve been having kidney stones for 19 months. My primary doctor finally sent me to a urologist. My main concern is I have 9 cyst’s on my left kidney and I have lesions on my right. I’m really scared at this point. Should I be nervous? I’m doing the 24 hr urine test now. Also doing blood work and ultra sound this week. Feeling real scared.

  23. Rhonda Kitter

    How long does it take for a lab to generate the results from a Super Saturation Urine Test?

    • Fredric Coe, MD

      Hi Rhonda, To calculate supersaturation requires a full set of stone related analytes, so the time to reporting is the same as that for the report itself. A common turnaround time for commercial labs is 24 hours from receipt. Regards, Fred Coe

  24. FCBarca

    What is the importance of the stop time for a 24 hr urine and what if this is not properly recorded or provided later as an estimation?

    • Fredric Coe, MD

      Hi, A great question. The samples are calibrated for 24 hours. The clock starts when you empty your bladder, discard the urine, and write down the time. All the urine produced from then on will be collected. As close as possible to 24 hours later you empty your bladder, put that urine into the container, and write down the time – the stop time. The time difference between the start and stop is taken as the clock time -in hours – over which you collected. All excretion rates are calculated by dividing the amount of – as an example – calcium in the total urine volume by the hours between the start and stop time. So the stop time is crucial for calculating all excretion rates. Without it, no calculation. With an error in it, the excretion rates are in error and will be misleading. Regards, Fred Coe

  25. Su W

    Nice explanation. Thank you.

  26. Henry Fung

    After collecting the 24 hrs urine test. How long can the specimen wait before we send it to lab corp?
    What if it takes more then 24hrs after the collection will that change the urine chemistry in the sample?

    • Fredric Coe, MD

      Dear Henry, I do not know anything about LabCorp procedures but I do know that Litholink needs samples back within 4 days or some of the measurements in the sample will have changed. I know this because at one time I owned Litholink and we made a study of the matter. To be certain I would send it back promptly. Best, Fred Coe


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