Normal ranges for ALT liver tests are 7 to 55 units per liter and 8 to 48 units per liter for AST, states Mayo Clinic. These ranges are established for adult men and may differ with women and children. Normal ranges may also vary depending on the laboratory.
Abnormal liver test results typically mean that liver disease is present, according to Mayo Clinic. Liver tests are also used to determine what treatments should be used and to help monitor the progression of the disease. Certain medications and food can affect results; patients should report any food and medication intake to the doctor before for accurate results.