Urine urea nitrogen is a measure of protein breakdown in the body. A test can be done to measure the amount of urea in the urine.

This test is mainly used to determine a person's protein balance and the amount of dietary protein needed by severely ill patients. It is also used to determine how much protein a person takes in.

Urea is excreted by the kidneys, so excretion of urea can reflect kidney function.

A 24-hour urine sample is needed.

• On day 1, urinate into the toilet when you get up in the morning.
• Afterwards, collect all urine in a special container for the next 24 hours.
• On day 2, urinate into the container when you get up in the morning.
• 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.

For an 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 the infant. For males, place the entire penis in the bag and attach the adhesive to the skin. For females, place the bag over the labia. Diaper as usual over the secured bag.

This procedure may take a couple of attempts -- lively infants can move the bag, causing the urine to be absorbed by the diaper. Check the infant frequently and change the bag after the infant has urinated into it. Drain the urine from the bag into the container provided by your health care provider.

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

No special preparation is needed. If the collection is being taken from an infant, a couple of extra collection bags may be necessary.

The test involves only normal urination, and there is no discomfort.