The normal level of liver enzymes for adult men are 7 to 55 units per liter of alanine aminotransferase, or ALT, and 8 to 48 units per liter of aspartate aminotransferase, or AST, notes Mayo Clinic. Normal alkaline phosphatase, or ALP, levels fall between 45 and 115 units per liter.
The normal ranges of ALT, AST and ALP for women and children are somewhat different, and the values for men differ depending on diet and current medications.
Liver function tests are generally taken in conjunction with kidney function tests and electrolyte measurements, states eMedicineHealth. The measurements are taken to determine the individual's risk of developing liver disease or to check the progression of a present liver disease, notes Mayo Clinic.