Macro-AST: A benign cause of persistently elevated aspartate aminotransferase

Macro-AST may be the cause of unexplained elevated AST, particularly when identified in the context of laboratory screening, or in an otherwise healthy child. Other elevations in enzymes (and some hormones) may be explained by the macro-enzyme/macro-hormone phenomenon. Laboratory methods such as PEG-precipitation, electrophoresis, immunoprecipitation or gel filtration should be undertaken prior to other invasive or expensive tests if a macro-enzyme is suspected.