Urea nitrogen; urine

Alternative names:

urine urea nitrogen; UUN

How the test is performed:

A 24-hour urine sample is needed.
The health care provider will instruct you, if necessary, to discontinue drugs that may interfere with the test.

• On day 1, urinate into the toilet upon arising in the morning.
• Collect all subsequent urine (in a special container) for the next 24-hours.
• On day 2, urinate into the container in the morning upon arising.
• Cap the container. Keep it in the refrigerator or a cool place during the collection period. Label the container with your name, the date, the time of completion, and return it as instructed.

Infant:
Thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on your infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia. Place a diaper over the infant (bag and all). The infant should be checked frequently and the bag changed after the infant has urinated into the bag. For active infants, this procedure may take a couple of attempts--lively infants can displace the bag, causing an inability to obtain the specimen. The urine is drained into the container for transport to the laboratory.

Deliver it to the laboratory or your health care provider as soon as possible upon completion.

How to prepare for the test:

No special preparation is necessary for this test, but if the collection is being taken from an infant, a couple of extra collection bags may be necessary.

How the test will feel:

Urinate in the normal manner but collect all the urine in the container provided.

Risks:
There is essentially no risk.

Why the test is performed:

This test is mainly used to assess the amount of dietary protein needed by severely ill patients. Urea is a measure of protein breakdown in the body.

Urea is excreted by the kidneys, so excretion of urea can reflect kidney function. The urine urea excretion can be measured to obtain a ratio between the plasma (blood) urea and the urine urea; this ratio (U/P urea) is an indicator of how well the kidneys are able to filter and excrete urea from the bloodstream.