[Diagnosis of Autoimmune Hepatitis]

Autoimmune hepatitis (AIH) is an immune-mediated inflammatory liver disease with an uncertain cause. The diagnosis of AIH is based on the characteristic clinical and laboratory findings (elevated liver enzyme and hypergammaglobulinemia), the presence of characteristic autoantibodies, and compatible histological abnormalities. AIH lacks a signature diagnostic marker, and the diagnosis requires the exclusion of other diseases (viral hepatitis, alcoholic liver disease, non-alcoholic steatohepatitis, drug-induced liver injury, Wilson's disease, and hereditary hemochromatosis). Therefore, collaboration between the clinical physician, laboratory medicine experts, and pathologists is important for a diagnosis. In December 2022, the Korean Association for the Study of the Liver (KASL) clinical practice guidelines were established. This review article summarizes the diagnosis part of these guidelines.