Reasons, Results & Considerations for AST Blood Test

Submitted on March 27, 2012

AST Blood Test

The blood test for AST or aspartate transaminase is a test to reveal injury to certain organs, specifically the liver. Aspartate transaminase is an enzyme that is responsible for the creation of glutamate and oxaloacetate. Both of these are inputs that go into a crucial system called the citric acid cycle. This is the cycle where energy is created by the creation of guanine triphosphate and adenosine triphosphate. These are then converted into their diphosphate forms and energy is released. AST is present in nearly all cells, but is available in the liver, heart, and the brain abundantly. While this test was initially used to check for heart disease it is now used to check for only liver inflammation.

Reason Why It is Performed

The AST test is used when a patient turns up at the doctor’s office with a case of jaundice. One of the first tests that are ordered is a gamma glutamyl transaminase test along with an alanine transaminase test or an alkaline phosphatease test. All of these tests when combined will give a clear indication of liver damage that is caused by acute inflammation. This is usually what happens when there is a liver infection as is the case in viral hepatitis but it can also be because of alcoholic liver disease.


When the blood tests that you undergo show results that are greater than 40 IU/L, then this is a sign of acute liver inflammation. This occurs because these enzymes that are normally within the liver tend to leak out into the blood stream because of the swelling in the liver. The first order of treatment is to reduce the inflammation in the liver and to bring down the counts to more manageable levels. This is mostly done by administering vitamin K injections that can reduce the inflammation.

Viral Hepatitis and Alcoholism

Viral hepatitis and alcoholism are usually the most predominant reasons for the liver to become inflammed. Viral hepatitis is usually caused by having contaminated food or water. This can usually be prevented by cooking food very thoroughly and ensuring that you only drink bottled water. Alcoholic liver damage causes a condition called cirrhosis. In this condition, liver tissue that is damaged does not get replaced and instead scar tissue develops in the liver. This is permanent liver damage that is usually fatal over the course of time.