Urea Nitrogen Clearance (Urine)
Does this test have other names?
Urine urea nitrogen, 24-hour urine test
What is this test?
This test measures the amount of urea nitrogen in your urine.
Urea nitrogen is a waste product made when your liver breaks down protein. It's carried
in your blood, filtered out by your kidneys, and removed from your body in your urine.
If your liver isn't healthy, it may not break down proteins the way it should. And
if your kidneys aren't healthy, they may not properly filter urea. Either of these
problems can lead to changes in the amount of urea nitrogen in your body.
If you don't have enough fluid in your body (are dehydrated), you may have extra urea
in your blood because you aren't passing much urine.
Why do I need this test?
You may have this test if your healthcare provider wants to find out how healthy your
kidneys are or wants to see whether your medical treatment is working.
You may also have this test to look at your protein balance.
What other tests might I have along with this test?
Your healthcare provider may also order blood tests, usually within 48 hours of this
test. These tests may include:
Your provider may also order a kidney X-ray or a kidney biopsy. For a biopsy, a tiny
piece of your kidney tissue is removed and looked at.
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses
to do the test. Even if your test results are different from the normal value, you
may not have a problem. To learn what the results mean for you, talk with your healthcare
Results are given in grams per 24 hours. A normal range is about 12 to 20 grams/24
Lower levels may mean that you don't have enough protein in your diet or that you
have kidney problems.
Higher levels may mean that you are getting too much protein in your diet or your
body is breaking down too much protein.
How is this test done?
This test requires a 24-hour urine sample. For this sample, you must collect all the
urine you make for 24 hours. Empty your bladder completely first thing in the morning
without collecting it and note the time. Then collect your urine every time you go
to the bathroom for the next 24 hours.
Does this test pose any risks?
This test poses no known risks.
What might affect my test results?
Certain medicines can affect your results.
How do I get ready for this test?
You don't need to prepare for this test. But be sure your healthcare provider knows
about all medicines, herbs, vitamins, and supplements you are taking. This includes
medicines that don't need a prescription and any illicit drugs you may use.