Uric acid is a waste product formed by the breakdown of certain types of amino acids called purines. Amino acids are the building blocks of proteins. Foods that are high in purines include liver, kidney, peas and beans (legumes), and some fish. Uric acid is also produced by the breakdown of the body's cells.

Most of the uric acid is eliminated from the body in urine; the rest passes out of the body in stools. However, if excess uric acid is being produced or the kidneys are not able to remove it from the blood normally, the level of uric acid in the blood will increase.

High levels of uric acid in the blood can cause the excess uric acid to be deposited in the body's joints, leading to a form of arthritis called gout. If gout remains untreated for several years, uric acid crystals can build up in the joints and surrounding connective tissues, forming hard deposits called tophi. High levels of uric acid may also lead to kidney failure or result in the formation of uric acid kidney stones. 

This test is done on a blood sample taken from a vein.

Uric Acid in Blood
Results

Normal

Normal values may vary from lab to lab.

Greater than normal values may mean

• Increased levels of uric acid in the blood indicate that a person is likely to develop or may already have gout. High levels may also indicate that kidney disease or damage is preventing the removal of uric acid from the blood.
• Increased levels of uric acid can also be caused by the increased breakdown of body cells caused by some types of cancer (including leukemia and multiple myeloma), hemolytic anemia, sickle cell anemia, or heart failure. Other conditions that can increase uric acid levels in the blood include alcoholism, lead poisoning, preeclampsia, liver disease (such as cirrhosis), lipid disorders (such as hyperlipidemia), obesity, psoriasis, hypothyroidism, and low blood levels of parathyroid hormone.
• Starvation, malnutrition, or lead poisoning can also increase the amount of uric acid in the blood.

Lower than normal values may mean

• Low levels of uric acid may indicate severe liver disease, heavy metal poisoning, Wilson's disease, or some types of cancer. Also, syndrome of inappropriate antidiuretic hormone (SIADH), a condition that causes large amounts of fluid to build up in the body, can cause low levels of uric acid in the blood.
• A very low-protein diet can also cause low levels of uric acid in the blood.
• Some people lose more uric acid through the urine, resulting in low levels of uric acid in the blood.