Macro-aspartate Aminotransferase: misleading finding in a patient with nonalcoholic fatty liver disease

Persistent elevation of aspartate aminotransferase (AST) activity in serum due to the presence of a macro-enzyme form of AST (macro-AST) may lead to diagnostic confusion in many clinical conditions, particularly in those associated with chronic liver disease. We present a case of macro-AST in a patient with non-alcoholic fatty liver disease in which polyethylene glycol precipitation confirmed the cause of disproportionately elevated AST as macro-AST.