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.

>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.

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

  1. Patricia

    what is the self pay cost for the study from Litholink:

  2. Laura M

    My husband is a U of C patient and was given an order by his Dr. to complete a 24-hour urine collection. We were able to print out the order from My Chart but did not receive instructions on where to go for pick-up/drop-off or how to go about this. Any guidance on next steps?

    • Fredric Coe, MD

      Hi Laura, I copied this to our clinical secretary and I have asked her to fix whatever problems your husband has encountered. I apologize. Regards, Fred Coe

  3. Dhanya

    Iam very glad to read the findibg you have given.. Thank you so much Sir.My husband has kidney stone disease. He is 40 year old obez, diabetic man with family history of kidney stones, He used to get 3-4 stones in a year. Stone analysis done once showed calcium oxalate stones.24 hour urin analysis done once showed normal results. ( test conditions were not according to what you have suggested )Since one and half years he is following low carb moderate protein healthy plant based diet. He didnt loose any single kg weight. But since 1and half years he didnt have any stone. But in december 2022,he got stone pain and both ureter got blocked ended up in URS procedure and stent etc. CT repirt showed multiple stones largest was 9mm. Now my dout is when can l ask for a 24 hour urin analysis, since he is admitted in hospital for stent removal and one stone removal now.hope you will answer my question.

    • Fredric Coe, MD

      Hi Dhanya, Most important is the analysis of the stone. Is it uric acid, calcium oxalate, calcium phosphate?? Everything hinges on that. 24 hour urine testing is not best done when stents are in place but when they are gone and he is eating normally. Regards, Fred Coe

  4. Margaret Fagerholm

    Dr. Coe, Is there a site where I can obtain a 24 hr urine as needed? I an 69. I have had three 24 hour urine studies, two a year ago, and one in Nov. I had incidental 3 stones noted on CT(for abd pain), largest 4mm. Based on the first two studies, dietary correction was deemed adequate with decreased Ox., although Ca24 was still elevated at 345. My urologist (atonic bladder)felt nothing more need be done since stone load unchanged( second CT for SBO) I kept the nephrology appt which was 10 months later. The third study this Nov showed SS CaOx 6.10, Ca24 of 609!, Ox24, Cit24 1207, SSCaP 2.53, pH 6.1,. Dietary: Na24 126, K24 57, Mg24 229, P 24 1.092, Nh4 24 61, Cl 24 148, Sul 24 UUN24 44, PCR 1.3 … It was felt to be hereditary IH and not dietary therefore was started on 25mg Chlorothalodone. I am just taking 12.5mg currently until side effects (dizziness) diminish, but after reading your articles realized that 2 days before I took the test, I had a sugar blowout, and wonder if these results are the result of that. I don’t want to take more RX if it is not needed, and I also have to cath due to atonic bladder, l drink 64oz /day and do low carb /moderate protein (80gm) so my sodium is already lower. I am not scheduled until Dec 2023 to see the Nephrologist. Repeat urine is not for 6 months. Have also tried to schedule with your office, but no result yet. I several other health issues that complicate the matter included hx of SBO, ongoing intermittent ab pain, with abnormal Small Bowel (undiagnosed) that I am still waiting to be seen for as well as a neurologic dx with complications. Both the gut and neurological issues may require surgery. I would like to check results sooner while I am still on the 12.5 mg , then again as things change. I am in the medical field and in the short term could make some headway on my own for now.
    Thank you,

    • Fredric Coe, MD

      Hi Margaret, It is a very complex problem. If you had chosen a telehealth visit here, there is no reason against it. My secretary is at 773 702 1475 and you should call and remind her to take care of the matter. Regards, Fred Coe

  5. Liz S

    Having PCNL surgery in two weeks. Should the urine test be done before or after or does it matter?

    • Fredric L Coe, MD

      Hi Liz S, I matters. Before may be faulty if there is obstruction, so not ideal. After may be faulty if you are not back on your normal diet and doing your normal work, so wait until both are true. Regards, Fred Coe

  6. Parick Pruchnik

    Good advice! Where do I find sample email to request 24 hour urinalysis to my urologist?


  7. Patrick Pruchnik

    Good advice! I understand that there is a sample email to send to the urologist requesting (demanding?) the 24 hour urine test(s). Please advise.


    • jharris

      Hi Patrick,
      There is no sample email but you can simply ask your doc to order you (any doc can order it) a 24 hour urine collection panel for kidney stone risk. IF they say no, tell them you want it because you want to know why you are forming stones so you can get on a treatment plan to stop forming stones.

  8. Robert McHugh

    I am a U of C patient and received the collection containers and will complete my collection. I need the instructions for collection and drop off. It was 3 or 4 sheets and i cant find it. can you email it to me? rmchugh4@yahoo.com my number is 312 399 8270 birthdate 11/27/1973

    • Fredric L Coe, MD

      Hi Robert, I will see to this, and hope it has already been taken care of. Fred

  9. Dr. Sanjeev Mehta

    I am a Pathologist having own laboratory exclusively for Urinary Stone disease evaluation. I am doing 24 hrs Urine Metabolic test with Super-saturation. I want to know , can we opt for State (single sample) Urine Metabolic profile in stead of 24 hrs collection? Has any done comparative study about that ?
    I am asking this because many clinicians wants to get Urine Metabolic test on single (state) collection because many patients do not turn out for 24 hrs collection. Thanks

    • Fredric L Coe, MD

      Hello Dr Mehta, In our CRC research we find urine calcium, oxalate, pH, volume, supersaturations – more or less everything – change over the day and especially overnight. So I think a single sample is not a good idea. It costs as much to make the measurements, and the results will not represent the average for a 24 hour day but only some random part of it – very misleading. I am against the idea with all my heart. Best, Fred

    • Dámaris Pérez-Pagán

      I am investigating how a 24 urine sample could be affected if not kept in Ice or refrigerated during collection could you explain to me? I am a nurse Thanks in advance

      • Fredric L Coe, MD

        Hi Damaris,

        If the urine has a proper preservative, refrigeration is not needed. Litholink is the only national vendor that has exact methods for the collection and analysis and I would recommend using it for your patients. I founded LL in 1995 and sold it to Labcorp in 2006 so have no financial relationship to the company. Regards, Fred


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