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.


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

  1. linda

    i am 68yrs old and about to order a 24hr urine collection. I have a kidney stone in the upper lobe. My dr won’t arrange this for me, he says 80% are oxalate and to cut back on salt, sugar and drink plenty….but i want to know what’s going on and how to slow them from growing and to make a ”correct” informed decision on a diet plan for the specific type of stone…..do you have any suggestions please for what i ask for when picking up this 24hr collection kit. thank you very much for you time.

    • Fredric L Coe

      Hi Linda, You are best off using a commercial kidney stone urine vendor, Litholink is the best of these. If your urine testing is not done by a vendor I am afraid quality will be variable. I would specifically ask your urologist or PCP to order a Litholink 24 hour urine. They provide collection and mailback materials, and superb instructions and reporting otherwise unavailable. ALthough I founded Litholink I sold it to Labcorp in 2006 and have no financial ties to it or Labcorp. Regards, Fred Coe

  2. Joy

    Was so happy to find that site! I need help. I was diagnosed with MSK in 2017. Past years I had 1x/2x a year pain. Last week I had a bad flank pain which brought me to the the Primary Care Center. They found 1 kidney stone right side and reconfirmed a previously diagnosis of MSK in 2016. Doc wants me to do a routine urinalysis. I’d like to request for 24-hour urine test. What kind of 24H urine test should I request? I called a local lab and they told me there are diff types of 24H urine test (protein, creatine, etc).

    • Fredric L Coe

      Hi Joy, as I wrote in my first response to you, I found out last fall that Philippines lack 24 hour urine testing as needed for stones. I urged several influential people there to organize a national testing lab and believe that some efforts are underway, but so far as I know that has not as yet happened. It is impossible to improvise testing, it requires a special lab to get it right. Routine urinalysis is not itself helpful for stone prevention. Regards, Fred

  3. Dr B

    My lab insists on my patients doing a separate acidified urine collection for oxalate determinations. Doing 2-24 hr collections unfortunately deters many patients from being assessed. I have found a few papers showing that urine calciums do not require collection of urine in acid. I have been unsuccessful in finding a reference paper to support the use of one urine collection, which can be acidified at the lab after the patient brings it in. Any thoughts?

    • Fredric L Coe

      Hi Doctor, Litholink does ideal 24 hour urines with one collection. Using acid for oxalate is an old fashion long ago dismissed as unnecessary. I mention Litholink because I founded it, know how their methods work, and am free to recommend it as I sold it years ago to LabCorp and have no financial relationships of any kind with it or its parent company. We studied all this business of acid, recovery of oxalate, and found a single urine does it all. By now Litholink has done over a million or more such urines. Drop the lab you are using or get them into the modern world. Fred

  4. Huy Bui

    I am using supplements, do I need to stop using them for urine collection?

    • jharris

      Hi Huy,
      If your doc has prescribed the supplements continue. If you are taking them on your own accord, please stop 5 days and during the collection.
      Best, Jill

  5. A

    I am just about finished a 24 hour collection that I have done perfectly, and took the day off work to do… by sheer (bad) luck, I checked the clinic hours where I need to drop it off tomorrow and they have a “scheduled closure” all day. Can I finish this sample and just keep it in the fridge to submit a day later? I don’t think my boss is going to be happy with another day off for this… when I already know I will have to so two more of these tests… Thanks for your advice.

    • jharris

      Hi A,
      Best to call the lab that the testing kit came from to find out next steps.
      Good Luck, Jill

    • Fredric L Coe

      Hi A, putting a 24 hour urine in the fridge is not a good idea. I would finish it, room temperature, and bring it in a day later. Regards, Fred Coe

      • Kristen Wilker

        I was told to keep the jug in the fridge the whole time. Confused now

  6. John

    I have staff and Mercer in my blood from a fall had to have back surgery from that almost died I also have kidney stones in both kidneys right now the dr said my body just makes them some time they get stuck and I’m in the er are having surgery the dr is doing a 24 hr urine if my body is making these no matter what I eat are drink why would the dr need a 24 hr urine

    • Fredric L Coe

      Hi John, you have two apparently separate problems – infection from back surgery and bilateral stones. I can see why your physician wants to prevent more stones, and how stones and your back infection might interact poorly. The blood borne infection could infect the stones you have, and any obstruction of a kidney by a stone might lead to kidney infection from the bacteria in your blood from your back. So any amount of effort your physicians put forward is of great value here. The 24 hour collection is essential, and the article you posted on has a lot of the reasons. It would be easiest to begin by just reading it in detail – I know I am not the easiest writer to read and apologize in advance. Your physicians seem to be doing a fine job and have their hands full. Regards, Fred Coe


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