F2 and acute liver failure: The prothrombin time–international normalized ratio (PT-INR) is 2.05, 1.92, or 2.11, and antithrombin III (AT III) is 24.50%, which are proposed as prognostic criteria for the HBV-SALF (hepatitis B virus–related subacute-on-chronic liver failure), non-HBV-SLF (non-hepatitis B virus–related subacute liver failure), non-HBV-ACLF (non-hepatitis B virus–related acute-on-chronic liver failure), and HBV-ALF (hepatitis B virus–related acute liver failure) subclasses, respectively.