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 and beer.

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

A blood sample is needed. For information on how this is done, see: Venipuncture

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:

• 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
• Febuxostat
• 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 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 range between 3.5 and 7.2 mg/dL.

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.

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
• Syndrome of inappropriate antidiuretic hormone (SIADH) secretion
• Low purine diet

Additional conditions under which the test may be performed:

• Chronic gouty arthritis
• Injury of the kidney and ureter

Curhan GC, Mitch WE. Diet and kidney disease. In: Brenner BM, eds. Brenner and Rector’s The Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 53.