As Measured by
High ALT or AST levels may be a sign of a liver problem. When these two enzymes are compared, their levels can help identify the presence of liver toxins and liver disease/damage.
While it may appear that a high level of either AST or ALT may be enough to diagnose liver disease, the relationship of the two (AST:ALT ratio) can often pinpoint exactly what is going on.
The ratio also determines whether the condition is acute or chronic. An acute injury/condition will see a sudden spike in ALT, whereas, if it is a slower-progressing, chronic illness other organs will also become damaged, and AST levels will rise.
A ratio of <1 (higher ALT than AST) is optimal.
A ratio of 1 (equal ALT and AST) indicates acute viral hepatitis or drug-related liver toxicity.
A ratio of >1 (higher AST than ALT) indicates cirrhosis.
A ratio of >2 (AST twice that of ALT) indicates alcoholic liver disease - particularly where GGT is also elevated.