5. Aspartate aminotransferase and alanine aminotransferase

Abstract

A 59-year-old female presented to the headache center with complaints of recurring headaches over the past few months. She had not been sleeping well, her headaches were worsening, and she was experiencing frequent hot flashes. Laboratory studies were unremarkable except for an elevated aspartate aminotransferase (AST) value of 175 U/L. The patient drank alcohol occasionally and exercised frequently. The physician requested that the test be repeated in 2 weeks to confirm the abnormal result and instructed the patient to avoid alcohol use and strenuous exercise during that period. Repeat testing 2 weeks later showed an AST of 164 U/L along with the following results: hepatitis A total antibody, positive; hepatitis A IgM antibody, negative; hepatitis C antibody, negative; iron, 17.4 μmol/L; total iron binding capacity, 48 μmol/L; and transferrin saturation, 36%. The patient was known to have immunity to hepatitis B. The persistently elevated AST was suspected to be caused by certain medications that she was taking. Testing was repeated in another 2 weeks along with a hepatic function panel and showed the following results: activated partial thromboplastin time (APTT), 30.5 s; prothrombin time (PT), 10.8 s; γ-glutamyltransferase (GGT), 15 U/L; albumin, 42 g/L; total bilirubin, 5.