Alanine transaminase (ALT) blood test

What is Alanine transaminase (ALT) Blood Test?

An Alanine transaminase (ALT) blood test is a commonly ordered test. It measures the levels of ALT in your blood, which is a specific type of enzyme found in your liver and other tissues. ALT is released into your bloodstream when your liver or other tissues are damaged. Your healthcare provider will use your test results to help diagnose and monitor problems in your liver.

Preparing for ALT Blood Test

A healthcare provider caring for you should provide instructions regarding any preparation requirements or additional information. Generally, no special preparations or fasting before the test is required, although your healthcare provider may instruct you on how to best prepare.


Your healthcare provider will perform a blood draw. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. Then, the needle will be removed.

Once the blood is collected, the sample will be sent to a lab. A certified lab technician will perform the ALT test on the blood sample.

Types of ALT Blood Test

There are two types of ALT blood tests:

  • A complete liver panel
  • An ALT test alone

A complete liver panel is a group of tests to diagnose and monitor liver diseases. This panel typically includes bilirubin, albumin, ALT, alkaline phosphatase, and gamma-glutamyltransferase. Your health care provider may use this panel to evaluate your liver function.

An ALT test alone is a specific test to measure the level of ALT in your blood. Your healthcare provider may use this test to evaluate your liver function. The test may be used to diagnose liver diseases, damage due to medications, alcohol, or toxins, or to monitor the effectiveness of treatment.


The risks associated with an ALT blood test are minimal. You may experience slight discomfort or pain when the needle is inserted.

Why is the ALT Blood Test Ordered?

This test is ordered to help diagnose and monitor various liver diseases, such as hepatitis, cirrhosis, and jaundice. The test can also be used to determine the cause of abnormal liver enzyme levels.

When is ALT Blood Test Ordered?

Your healthcare provider may order an ALT blood test if you are experiencing signs and symptoms suggestive of liver damage, such as fatigue, jaundice, or abdominal pain. The test is also used to monitor the effectiveness of treatment for liver diseases. Your healthcare provider may order this test on a regular basis to assess your condition.