@turquoise-- I agree with you but an AST test is not enough to determine organ damage or disease. Like the article said, various factors can affect results of the test.
Aside from this though, when organ damage has reached a certain extent, the AST test might not give very accurate results.
A friend of mine had liver failure and then a liver transplant. Right before the transplant, the AST gave low test results despite the organ being completely diseased. Since no more damage was actually possible to the organ, AST amounts in the blood was coming back normal.
So a doctor diagnosis is always necessary in addition to the AST.