AST (aspartate aminotransferase) is an enzyme found in high amounts in liver, heart, and muscle cells. It is also found in lesser amounts in other tissues.
This article discusses the test to measure the amount of AST in the blood.
How is the Test Performed?
A blood sample is needed. It is usually taken from a vein. This is called a venipuncture .
How will the Test Feel?
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why is the Test Performed?
Normal Results for AST
The normal range is 10 to 34 IU/L.
Note: IU/L = international units per liter
Note: 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.
What Abnormal Results Mean
Increased AST levels are usually a sign of liver disease. Liver disease is even more likely if other liver-related blood tests are abnormal.
An increase in AST levels may be due to:
- Cirrhosis (scarring of the liver)
- Death of liver tissue
- Heart attack
- Lack of blood flow to the liver (liver ischemia)
- Liver cancer or tumor
- Medicines that are toxic to the liver
- Mononucleosis ("mono")
- Muscle disease or trauma
- Pancreatitis (swollen and inflamed pancreas)
AST levels may also increase after:
- Burns (deep)
- Heart procedures
Veins vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Risks associated with having blood drawn are slight but may include:
- Bleeding from where the needle was inserted
- Fainting or feeling light-headed
- Hematoma (blood collecting under the skin)
- Infection (a slight risk any time the skin is broken)
AST levels may rise during pregnancy and after exercise.
Berk P, Korenblat K. Approach to the patient with jaundice or abnormal liver tests. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 149.
Pratt DS. Liver chemistry and function tests. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010:chap 73.
|Review Date: 1/21/2013
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 A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.
Learn more about AST
Drugs associated with:
- Alcoholic Cirrhosis
- Biliary Tract and Hepatic Tumor
- Heart Attack
- Hepatic Tumor
- Liver and Pancreatic Disease
Micromedex® Care Notes:
- Acute Coronary Syndrome
- Fulminant Hepatic Failure
- Muscular Dystrophy
- Myocardial Infarction