Reasons, Preparation, Method and Results of Alanine Aminotransferase Test

Submitted on March 27, 2012

What Is Alanine Aminotransferase (ALT)?

Alanine Aminotransferase or ALT is an enzyme that is present in the cells of the heart and liver. It is also referred to as serum glutamic pyruvic transaminase or SGPT. When damage to the heart or liver occurs, this enzyme is released in the bloodstream. Conditions of the liver such as viral hepatitis and heart disruptions such as a heart attack result in elevated ALT levels in the blood. Certain medications can also cause a rise in blood ALT levels. An ALT liver test may be done to detect any damage that may have occurred in the liver.

Usually low alanine aminotransferase levels are found in the blood, but when there is disease or damage to the liver, an increased quantity of the enzyme is released by the liver cells. High ALT levels in the bloodstream are most commonly caused by liver conditions. An ALT test is usually administered along with certain other tests such as alkaline phosphatase, lactate dehydrogenase or LDH, bilirubin and aspartate aminotransferase or AST. All these tests are used for detecting damage to the liver.

Reasons for Performing the Alanine Aminotransferase Test

An ALT or SGPT test is performed in order to detect the type of liver disease that is present such as hepatitis or cirrhosis caused by excessive use of alcohol and drugs or due to viral infection; to determine the cause of jaundice, whether due to disease of the liver or disorder of the blood; and to track the effects of medications for lowering cholesterol levels and other medicinal drugs that can potentially cause liver damage.


Usually strenuous physical activity must be avoided prior to the test. Medications can cause interference with the test results and as such if the individual is on any type of medication, the doctor must be informed. The medication may have to be discontinued for a few days before the test. Herbs such as valerian and echinacea are also known to affect test results and as such may have to be discontinued as well. The doctor must also be informed regarding allergies to any medications that the individual may have. It is also important to notify the doctor if the individual is pregnant. Any other doubts or questions about the test can also be discussed with the doctor.

Method Used

The test is done by taking a sample of blood from a vein of the upper arm of the individual.

Interpretation of Test Results

The results of an ALT test are obtained in twelve hours. High levels of ALT may be indicative of viral hepatitis, reactions to drugs, lead poisoning or necrosis. Moderately high levels of ALT are indicative of hepatitis, mononucleosis or excessive alcohol consumption. Slightly high ALT levels can be indicative of fat deposits in the liver, cirrhosis or medications. If the test results are not normal, then other tests will be conducted to determine the cause of elevated ALT levels.