The Test Sample
What is being tested?
Uric acid is produced by the breakdown of purines. Purines are nitrogen-containing compounds found in the cells of the body, including our DNA. As cells get old and die, they break down, releasing purines into the blood. To a lesser extent, purines may come from the digestion of certain foods, such as liver, anchovies, mackerel, dried beans and peas and certain alcoholic drinks, primarily beer. Most uric acid is removed from the body by the kidneys and is excreted in the urine, with the remainder eliminated in the stool. This test measures the level of uric acid in the blood or urine.
If too much uric acid is produced or not enough is excreted, it can accumulate in the body, causing increased levels in the blood (hyperuricemia). The presence of excess uric acid can cause gout, a condition characterized by inflammation of the joints due to the formation of uric acid crystals in the joint (synovial) fluid. Excess uric acid can also be deposited in tissues such as the kidney, leading to kidney stones or kidney failure.
The accumulation of too much uric acid is due to either increased production, decreased elimination, or a combination of both. Elevated levels of uric acid can occur when there is an increase in cell death, as seen with some cancer therapies or, rarely, as an inherited tendency to overproduce uric acid. Decreased elimination of uric acid is often a result of impaired kidney function due to kidney disease.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm. A 24-hour urine sample may be collected for the urine uric acid test.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation may be needed. Some institutions, however, recommend fasting for 4 or more hours. Follow any instructions provided and be sure to discuss with the health care provider any medications being taken before having this test performed.