uric acid in urine test

test overview

the uric acid urine test measures the amount of uric acid in a sample of urine collected over 24 hours.

uric acid is made from the natural breakdown of your body's cells. it's also made from the foods you eat. your kidneys take uric acid out of your blood and put it into urine so that it can leave your body.

but if your body is making too much uric acid, the level in the urine can get too high. and if your kidneys aren't working the way they should, the level of uric acid in the urine can get too low.

high levels of uric acid can cause crystals to form in joints. this causes a painful problem called gout. if gout isn't treated, the crystals can build up and form hard lumpy deposits called tophi.

high uric acid levels can also cause kidney stones.

why it is done

this test is done to:

• see if kidney stones were caused by high uric acid levels.
• find the cause of a high level of uric acid in the blood and help choose the proper treatment.

how to prepare

in general, there's nothing you have to do before this test, unless your doctor tells you to.

for 24-hour urine collection, your doctor or lab will usually give you a large container that holds about 4 l (1 gal).

many medicines can change the results of this test. be sure to tell your doctor about all the over-the-counter and prescription medicines you take.

how it is done

a uric acid urine test is usually done at home. you must collect all the urine you produce in a 24-hour period.

• 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 of your urine. your doctor or lab will usually provide you with a large container that holds about 4 l (1 gal). the container may have a small amount of preservative in it. urinate into a small, clean container. then pour the urine into the large container. don't touch the inside of either container with your fingers.
• keep the large container in the refrigerator when you aren't using it.
• empty your bladder for the last 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.

how it feels

this test usually doesn't cause any pain or discomfort.

risks

there are no known risks from having this test.

results

each lab has a different range for what's normal. your lab report should show the range that your lab uses for each test. the normal range is just a guide. your doctor will also look at your results based on your age, health, and other factors. a value that isn't in the normal range may still be normal for you.

many conditions can change uric acid levels. your doctor will talk with you about any abnormal results that may be related to your symptoms and past health.