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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 health care 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

  • Jaundice, or yellow skin and whites of eyes

  • Nausea and vomiting

  • Lack of appetite

  • Tiredness

You may also have this test if you have a family history of liver illness or drink an abnormally high amount of alcohol. 

What other tests might I have along with this test?

Your doctor 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 health care provider.

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

  • Infants 0 to 5 days old: 35 to 140 units/L

  • Children younger than 3 years: 15 to 60 units/L

  • Children 3 to 6 years old: 15 to 50 units/L

  • Children 6 to 12 years old: 10 to 50 units/L

  • Youths 12 to 18 years old: 10 to 40 units/L

  • Adults: 0 to 35 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 the following:

  • Liver disease

  • Muscle injury

  • Damage to your kidneys

Extremely high levels of AST – 50 times the upper limit of normal – may mean you have a disease like viral hepatitis, liver injury from drugs or toxins, or shock liver, a type of hepatitis. 

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 or if you take para-aminosalicylic acid or erythromycin estolate, antibiotics that treats bacterial infections.

How do I get ready for this test?

You don't need to prepare for this test.  But, be sure your doctor 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.