Definition of Uric acid - urine:

Uric acid is a chemical created when the body breaks down substances called purines. Purines are found in some foods and drinks, such as liver, anchovies, mackerel, dried beans and peas, beer, and wine.

Most uric acid dissolves in blood and travels to the kidneys, where it passes out in urine. If your body produces too much uric acid or doesn't remove enough of it, you can get sick. High levels of uric acid in the body is called hyperuricemia.

This test checks to see how much uric acid you have in your urine.

See also: Uric acid - blood

How the test is performed:

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.

How to prepare for the test:

Your doctor may tell you to stop taking any drugs that may affect the test results. For example, high levels of vitamin C and dyes used during certain x-rays may cause incorrect results.

Drugs that can interfere with test results include:

• Alcohol
• Allopurinol
• Anti-inflammatory drugs (such as ibuprofen)
• Salicylates (including aspirin)
• Thiazide diuretics
• Probenecid

This list may not be all-inclusive.

How the test will feel:

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

Why the test is performed:

This test may be done to diagnose kidney stones. It may also be used to monitor people with gout, since many of these patients develop uric acid kidney stones.