GPT and animal viral hepatitis: The most common reasons for screen failure (subjects could fail more than 1 criteria) were elevated bilirubin (n = 47), elevated INR (n = 22), elevated ALT or AST (n = 28), elevated alkaline phosphatase (n = 4), positive viral hepatitis markers (n = 17), history of excessive alcohol consumption (n = 9), starting a new prescription in the preceding month (n = 4) and history of acetaminophen ingestion in the 3 days prior to enrollment (n = 3).