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Aspartate Transaminase

Does this test have other names?

AST, 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. This test can also be used to monitor liver disease.   

Why do I need this test?

Your healthcare provider might give you this test if he or she suspects that your liver is damaged.

You might have this test if you have these symptoms related to liver disease:

  • Dark-colored urine

  • Light-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 in the belly (abdomen), pain in the belly, or both

You may also have this test if you have a family history of liver illness or drink an abnormally 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 cause liver damage.

What other tests might I have along with this test?

Your healthcare provider may also order 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. 

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.

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

  • Males: 10 to 40 units/L

  • Females: 9 to 32 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 like 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 requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore. 

What might affect my test results?

Test results may be false-positive if you have diabetic ketoacidosis. They may also be false-positive if you take para-aminosalicylic acid or erythromycin estolate. These are antibiotics that treat bacterial infections.

How do I get ready for this test?

You don't need to prepare for this test.  But, be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.  

Medical Reviewers:

  • Fraser, Marianne, MSN, RN
  • Sather, Rita, RN