Aspartate Aminotransferase (AST): About This Test

Location of liver in the body

What is it?

An aspartate aminotransferase (AST) test measures the amount of AST in the blood. AST is an enzyme. When AST levels are higher than normal, it can mean that the liver or another organ is damaged or diseased.

Why is this test done?

This test is done to:

  • Check for liver damage.
  • Help look for liver disease, such as hepatitis. Liver disease may cause symptoms. These may include pain in the upper belly, nausea, vomiting, and sometimes jaundice.
  • Check to see how well treatment for liver disease is working.
  • Find out if jaundice was caused by a blood disorder or liver disease.
  • Keep track of the effects of medicines that can damage the liver.

How do you prepare for the test?

In general, there's nothing you have to do before this test, unless your doctor tells you to.

How is the test done?

A health professional uses a needle to take a blood sample, usually from the arm.

How long does the test take?

The test will take a few minutes.

What happens after the test?

  • You will probably be able to go home right away.
  • You can go back to your usual activities right away.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Where can you learn more?

Go to https://www.healthwise.net/patientEd

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