Persistently high serum aspartate aminotransferase level in an asymptomatic young patient.

Elevated liver enzymes, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), may commonly indicate liver injury. However, macro-AST is generally a benign condition that may be considered as pathologic by clinicians. A young man with isolated elevated AST for more than 10 years who have taken extensive tests and examinations was diagnosed with macro-AST in our article. Thus, in patients with isolated AST-elevation, polyethylene glycol (PEG) precipitation test was recommended to test whether macro-AST could be diagnosed.