KidsHealth says that a comprehensive metabolic panel includes tests for three liver enzymes: alanine aminotransferase, alkaline phosphatase and aspartate aminotransferase. Each enzyme has a different range for what is considered normal, according to MedlinePlus.
WebMD defines alanine aminotransferase as an enzyme found in the liver, pancreas, kidneys, muscles and heart. A healthy person usually has low levels of this enzyme in the blood, with a level of 8 to 37 international units per liter being normal, according to Medline Plus.
Experts from the American Association for Clinical Chemistry say that alkaline phosphatase is found in the edges of the cells that link together to form the bile ducts as well as in bone tissue. A bone or liver disorder sometimes causes an elevated level of this enzyme. MedlinePlus says its normal range in the blood is 44 to 147 international units per liter.
Aspartate aminotransferase is found in the liver, kidneys, skeletal muscles and heart. People who have had heart attacks, viral hepatitis or acute liver damage often have high levels of this enzyme, according to the Mayo Clinic. The normal range for this enzyme is 10 to 34 international units per liter, according to the MedlinePlus website.