Bilirubin needs to be around 60 to see visible jaundice.
AST is less specific than ALT – also produced in kidney, brain etc. But perhaps changes more quickly than ALT. Most important other source of AST and ALT is muscle – so check CK too, especially if bilirubin normal. Myopathies, viral myositis, muscular dystrophy can all present with “abnormal LFTs”.
Gamma GT is also found in other tissues so not 100% specific but typically suggests cholestasis or other biliary problem (together with alkaline phosphatase).
Alkaline phosphatase also produced in bone, so look at calcium, phosphate and vitamin D as well as signs of rickets or renal disease. Most common cause of isolated high alkaline phosphatase is benign transient hyperphosphatasaemia.
Falling transaminases can be ominous in situation of bilirubin, albumin, coagulation deteriorating…