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

The health care provider will use a needle to take blood from one of your veins, usually from the inside of the elbow or the back of the hand. The blood collects into an air-tight container or a hollow tube.

A laboratory specialist checks the blood sample for uric acid.

You should not eat or drink anything for 4 hours before the test. 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:

• Alcohol
• Ascorbic acid
• Aspirin
• Caffeine
• Cisplatin
• Diazoxide
• Diuretics
• Epinephrine
• Ethambutol
• Levodopa
• Methyldopa
• Nicotinic acid
• Phenothiazines
• Theophylline

Drugs that can decrease the level of uric acid in your body include:

• Allopurinol
• Azathioprine
• Clofibrate
• Corticosteroids
• Estrogen
• Glucose
• Guaifenesin
• Mannitol
• Probenecid
• Warfarin

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.

Your doctor may also order this test if you have had 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.

Greater-than-normal levels of uric acid (hyperuricemia) may be due to:

• Acidosis
• Alcoholism
• Diabetes
• Gout
• Hypoparathyroidism
• Lead poisoning
• Leukemia
• Nephrolithiasis
• 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
• SIADH
• Low purine diet

Additional conditions under which the test may be performed:

• Chronic gouty arthritis
• Injury of the kidney and ureter

Goldman L, Ausiello D. Cecil Textbook of Medicine. 22nd ed. Philadelphia, Pa: WB Saunders; 2004.

McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. St. Louis, Mo: WB Saunders; 2006.