Aspartate Transaminase

Does this test have other names?

AST, aspartate aminotransferase, serum glutamic oxaloacetic transaminase test, SGOT

What is this test?

This blood test is used to diagnose liver damage. Aspartate transaminase (AST) is an enzyme that is released when your liver or muscles are damaged. Although AST is found mainly in your liver and heart, AST can also be found in small amounts in other muscles.

Why do you need this test?

You may need this test if your doctor believes that your liver is damaged.

You might have this test if you have symptoms related to liver disease. These include:

• Dark-colored urine.

• Light or clay-colored stool.

• Yellowing of the skin or eyes (jaundice).

• Nausea and vomiting.

• Lack of appetite or weight loss.

• Weakness or tiredness (fatigue).

• Itching (pruritus).

• Swelling or pain in the belly.

You may also have this test if you have a family history of liver illness or drink a very large amount of alcohol. You may also have this test if you have a condition, such as diabetes, that may cause liver problems or if you take medicines that can affect the liver.

What other tests might you have along with this test?

You may also need the alanine aminotransferase (ALT) test. It's commonly used along with the AST test to look at your liver's function. ALT is an enzyme found in the liver. High levels of ALT can mean hepatitis. Other tests that check liver function are alkaline phosphatase, gamma-glutamyl transpeptidase, and total bilirubin.

What do your test results mean?

Test results may vary depending on your age, sex, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your doctor what your test results mean for you.

Results are given in units per liter (units/L). Normal ranges for AST are:

• Men: 14 to 20 units/L

• Women: 10 to 36 units/L

Women tend to have slightly lower levels than men. Older adults tend to have slightly higher levels than the normal range for adults.

If you have abnormally high levels of AST, you might have:

• Liver disease.

• Muscle injury.

• Heart attack.

• Pancreatitis.

Extremely high levels of AST may mean you have a disease, such as viral hepatitis, liver injury from medicines or toxins, or "shock liver." Shock liver is widespread liver damage caused by lack of oxygen or not enough blood supply.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. 

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect your test results?

Test results may be falsely lower if you have diabetic ketoacidosis or severe liver disease. Many medicines may also affect the results.

How do you get ready for this test?

You don't need to prepare for this test. Tell your doctor about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.