Test Overview
An alanine aminotransferase (ALT) test measures the amount of this
enzyme in the blood. ALT is found mainly in the liver,
but also in smaller amounts in the
kidneys
,
heart
, muscles, and
pancreas
. ALT formerly was called serum glutamic
pyruvic transaminase (SGPT).
ALT is measured to see if the liver is damaged or diseased. Low
levels of ALT are normally found in the blood. However, when the liver is
damaged or diseased, it releases ALT into the bloodstream, which makes ALT
levels go up. Most increases in ALT levels are caused by liver damage.
The ALT test is often done along with other tests that check for
liver damage, including aspartate aminotransferase (AST), alkaline phosphatase,
lactate dehydrogenase (LDH), and bilirubin. Both ALT and AST levels are
reliable tests for liver damage.