The diagnosis of acute liver failure in Japan required the presence of several features.
Diagnostic criteria for acute liver failure:
(1) The patient has the acute onset of symptoms and laboratory changes consistent with severe liver damage.
(2) Within 8 weeks of onset the patient has a coagulation abnormality - one or both of the following:
(2a) INR >= 1.5
(2b) prothrombin activity score <= 40% of standardized value
(3) Liver function prior to current episode is normal.
A patient with acute liver failure may be subclassified based on presence or absence of coma:
(1) without coma: no or Grade I hepatic encephalopathy
(2) with coma: Grade II to V hepatic encephalopathy
(2a) acute: encephalopathy develops <= 10 days after onset of symptoms
(2b) subacute: encephalopathy develops 11 to 56 days after onset of symptoms
(2c) late onset hepatic failure (LOHF): > 8 weeks
Excluded: acute on chronic liver failure, better classified as fulminant hepatitis
Included: other liver disease (autoimmune hepatitis, hepatitis B carrier, etc) with apparent normal liver function prior to current episode
Limitations: alternative explanation for the coagulation abnormality such as warfarin therapy
