At a Glance
Why Get Tested?
To screen for or monitor liver disease
When to Get Tested?
If your doctor thinks that you have symptoms of a liver disorder
A blood sample drawn from a vein in your arm
The Test Sample
What is being tested?
ALT is an enzyme found mostly in the liver; smaller amounts are also found in the kidneys, heart and muscles. Under normal conditions, ALT levels in the blood are low. When the liver is damaged, ALT is released into the blood stream, usually before more obvious symptoms of liver damage occur, such as jaundice (yellowing of the eyes and skin).
How is the sample collected for testing?
A blood sample will be drawn from a vein in the arm.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.