GPT and ischemia: Levels above 1000 units/L raise suspicion for processes that cause necrosis of hepatocellular tissue such as ischemia, viral hepatitis, or drug toxicity.2 Markedly elevated AST levels have also been described in acute pancreatitis and pancreatic carcinoma.3 Rarely, isolated calculous disease of the biliary tract with no hepatic disease or involvement can present with markedly elevated AST and ALT levels.