Important predictive variables include Degree of encephalopathy: Worse when encephalopathy is severe Patient age: Worse when age is < 10 or > 40 years PT: Worse when INR is prolonged Cause of acute liver failure: Better with acetaminophentoxicity, hepatitis A, or hepatitis B than with idiosyncratic drug reactions or Wilson disease Various scores (for example, King's College criteria or Acute Physiologic Assessment and Chronic Health Evaluation II [APACHE II] score) can predict prognosis in populations of patients but are not highly accurate for individual patients.