Acute liver failure is the appearance of severe complications rapidly after the first signs of liver disease (such as jaundice), and indicates that the liver has sustained severe damage (loss of function of 80-90% of liver cells). The complications are hepatic encephalopathy and impaired protein synthesis (as measured by the levels of serum albumin and the prothrombin time in the blood). The 1993 classification defines hyperacute as within 1 week, acute as 8-28 days and subacute as 4-12 weeks. It reflects the fact that the pace of disease evolution strongly influences prognosis. Underlying aetiology is the other significant determinant of outcome.