Uric acid - blood
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 if 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 blood.
See also: Uric acid - urine
How the Test is Performed
Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.
Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm.
Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects into a small glass tube called a pipette, or onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.
A laboratory specialist checks the blood sample for uric acid.
How to Prepare for the Test
You should not eat or drink anything for 4 hours before the test unless told otherwise. Your doctor may also tell you to stop taking any drugs that may affect the test results. NEVER stop taking any medicine without talking to your doctor.
Drugs that can increase the level of uric acid in your body include:
- Ascorbic acid
- Nicotinic acid
Drugs that can decrease the level of uric acid in your body include:
Why the Test is Performed
This test is done to see if you have high levels of uric acid in your blood. High levels of uric acid can cause gout or kidney disease.
Your doctor may also order this test if you have had or are about to have certain types of chemotherapy. Rapid weight loss, which may occur with such treatments, can increase the amount of uric acid in your blood.
Normal values fall between 3.0 and 7.0 mg/dL.
Note: Normal values may vary slightly from laboratory to laboratory.
What Abnormal Results Mean
Greater-than-normal levels of uric acid (hyperuricemia) may be due to:
- Lead poisoning
- Polycythemia vera
- Renal failure
- Toxemia of pregnancy
- Purine-rich diet
- Excessive exercise
- Chemotherapy-related side effects
Lower-than-normal levels of uric acid may be due to:
- Fanconi syndrome
- Wilson's disease
- Syndrome of inappropriate antidiuretic hormone (SIADH) secretion
- Low purine diet
Additional conditions under which the test may be performed:
Terkeltaub R. Crystal deposition diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 294.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.