When to Worry about ALT Levels? Alanine Transaminase (ALT) Test

Is there another non-liver condition that leads to high ALT levels?

Both AST and ALT can be synthesized and used by other tissues different than the liver, especially the skeletal muscle and the heart muscle. Thus, a heart attack and acute muscle damage can both cause a slight and temporary elevation of ALT levels. However, this increase is minimal compared to AST, and this marker is much more reliable in case of muscular damage or heart attacks.