Patient education: 24-hour urine collection (The Basics)

What is 24-hour urine collection? — This is when you collect all of the urine that your body produces over a 24-hour period. The urine is then measured and examined in a lab. Your doctor or nurse might check the level of certain substances in your urine. For example, they might check for certain proteins, hormones, or minerals. This can tell your doctor how well your kidneys are working.

Why might I need to collect my urine? — Your doctor might want you to do a 24-hour urine collection:

●To measure the levels of certain substances in your urine

●If you have symptoms of a kidney problem

●If you are at risk for kidney problems

●To check if you have an electrolyte or fluid imbalance

●To check how well your kidneys are working, if you have a known kidney problem or have had a kidney transplant

You might do a 24-hour urine collection as part of a "creatinine clearance" test. Creatinine is a waste product created by your muscles. When your kidneys are working properly, they filter creatinine out of your blood. The other part of a creatinine clearance test is a blood test called a "serum creatinine test."

How do I prepare for a 24-hour urine collection? — Your doctor or nurse will tell you if you need to do anything special to prepare. Ask questions if there is anything you do not understand.

You will be given 1 or more containers to collect your urine in. This is usually a large plastic bottle. You might also get a smaller cup or a special pan that fits over your toilet. These can be used to help collect the urine.

How do I collect my urine? — You will collect your urine over a 24-hour period. This starts on the morning of the first day and ends on the morning of the second day.

To collect your urine:

●Urinate as soon as you wake up on the first morning. But do not collect this urine. Flush it down the toilet as usual. Write down the exact time this happens. This is the start of your 24-hour collection period. For example, if you urinate at 7:10 AM, write that down.

●Collect the rest of your urine for the next 24 hours. If your start time was 7:10 AM, this means that you will collect all of your urine until about 7:10 AM the next day.

●During the 24 hours, it is important to collect all of your urine, even if it is a very small amount.

●Use the bottle given to you by your doctor or nurse to collect your urine. The sample should be kept cool, so it is best to store the bottle in the refrigerator.

•If you need to, you can urinate into a smaller cup or a special pan, and then empty that into your large collection bottle. Ask your doctor or nurse about these special cups or pans if you think that you want to use one.

●If you need to have a bowel movement, any urine passed with the bowel movement should be collected. Try not to include feces with the urine collection. But if some feces do get mixed in, do not try to remove them from the bottle.

●Write down the last time that you urinate during the 24 hours, even if it is not exactly at the 24-hour mark. So, for example, if you are collecting urine until 8:30 AM, and the last time you urinate is at 8:15 AM, write down 8:15 AM.

●Bring the container with the urine to your next appointment.

What do my results mean? — Your doctor or nurse will tell you when to expect your results, and will contact you with the results. Or if you use an online "patient portal," you might get an alert there when your results are ready.

If your tests show any abnormal results, your doctor or nurse will talk to you about what to do next. They might need to do more tests to figure out what the cause is.

If you do have a health problem, your doctor will work with you to come up with a plan for treatment.

More on this topic

Patient education: Serum creatinine test (The Basics)
Patient education: Renal function panel (The Basics)
Patient education: Electrolyte panel (The Basics)
Patient education: Cortisol test (The Basics)

Patient education: Collection of a 24-hour urine specimen (Beyond the Basics)