The uric acid urine test measures the amount of uric acid in a sample of urine collected over 24 hours. Uric acid is produced from the natural breakdown of your body's cells and from the foods you eat.

Most of the uric acid is removed from the body in urine. A small amount passes out of the body in stool. But if too much uric acid is being produced, the level in the urine will increase. If the kidneys are not able to remove it from the blood normally, the level of uric acid in the urine will decrease.

High blood levels of uric acid in the body can cause solid crystals to form within joints. This causes a painful condition called gout. If gout remains untreated, uric acid crystals can build up in the joints and nearby tissues, forming hard lumpy deposits called tophi. High levels of uric acid in the urine can cause kidney stones.

Why It Is Done

A uric acid urine test is done to:

• Check to see if kidney stones may be caused by high uric acid levels in the body.
• Find the cause of a high level of uric acid in the blood and help choose the proper treatment.

How To Prepare

No special preparation is required before having a uric acid urine test. It is not necessary to restrict fluids or foods before the test. Be sure to drink enough fluids during the 24-hour urine test to prevent dehydration.

During the collection period, do not drink alcohol because alcohol reduces the amount of uric acid eliminated by the kidneys.

Many medicines can change the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).

How It Is Done

A uric acid urine test is usually done on a sample taken from all the urine produced in a 24-hour period.

To collect your urine for 24 hours:

• You start collecting your urine in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated to mark the beginning of your 24-hour collection period.
• For the next 24 hours, collect all your urine. Your doctor's office or lab will usually provide you with a large container that holds about 1 gal (4 L). The container has a small amount of preservative in it. Urinate into a small, clean container and then pour the urine into the large container. Do not touch the inside of the container with your fingers.
• Keep the large container in the refrigerator for the 24 hours.
• Empty your bladder for the final time at or just before the end of the 24-hour period. Add this urine to the large container and record the time.
• Do not get toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.