The normal values of liver enzymes can vary depending on the laboratory that performs the test, but the general ranges are as follows:

a) Alanine aminotransferase (ALT): 7 to 55 units per liter (U/L). Elevated in: Hepatitis, alcoholic liver disease, non-alcoholic fatty liver disease, drug-induced liver injury. 

b) Aspartate aminotransferase (AST): 8 to 48 U/L. Elevated in: Hepatitis, alcoholic liver disease, heart attack, and muscle damage. 

c) Alkaline phosphatase (ALP): 40 to 129 U/L. Elevated in: Biliary obstruction, liver cancer, bone disease, pregnancy.

d) Gamma-glutamyl transferase (GGT): 8 to 61 U/L. Elevated in: Alcoholic liver disease, gallstones, hepatitis, pancreatitis.

Elevated levels of liver enzymes can be a sign of liver damage. However, it is important to note that elevated liver enzymes can also be caused by other conditions, such as muscle damage, heart attack, or pancreatitis. If you have elevated liver enzymes, it is important to see a doctor to determine the cause and get treatment if necessary.