A uric acid blood test measures the amount of uric acid in your blood. Uric acid is a normal waste product that your body makes when it breaks down chemicals called purines. Most of the uric acid dissolves in blood and travels to the kidneys, from where it passes out in urine. However, if your body produces too much uric acid or does not remove enough of it, you can get sick. High levels of uric acid in the blood, called hyperuricemia, can sometimes cause gout or kidney stones.

A uric acid test may be done as a blood test or a urine test. For a blood test, a healthcare professional will take a blood sample from a vein in your arm, using a small needle. The test measures the uric acid in milligrams (mg) and the blood in deciliters (dL), so youll see a number with units of mg/dL. Usually, you dont need any special preparations for a uric acid blood test, but many medicines, including aspirin, can affect your uric acid levels. Taking niacin (vitamin B-3) can also affect your results. So, be sure to tell your provider about all the medicines you take, but dont stop taking any medicines without talking with your provider first.

The uric acid blood test is ordered when a healthcare practitioner suspects someone has a high level of uric acid. Some people with high uric acid levels have a disease called gout, a common form of arthritis. People with gout suffer from joint pain, most often in their toes and other joints. The test is also ordered when cancer patients undergo chemotherapy or radiation therapy to ensure that uric acid levels are not dangerously high. The test can also be used to check kidney function after an injury, find the cause of kidney stones, and diagnose kidney disorders.