This study is aimed at elucidating the clinical pathogenesis of patients with hepatitis B virus–related liver failure (HBV-LF) and non-HBV-LF in a retrospective cohort study and developing new diagnostic or prognostic criteria for the subclassical classification of LF diagnoses, such as age; the number of days of hospitalization; and PT-INR, alanine aminotransferase (ALT), TBil, and antithrombin III (AT III) levels. This evidence concerns the gene GPT and Lassa fever.