Lactate dehydrogenase (LDH) is a nonspecific marker of hepatocellular injury. Extremely elevated LDH signifies massive hepatocyte damage, usually from ischemia or drug-induced hepatotoxicity (such as acetaminophen overdose). These patients will also have extreme elevations in AST and ALT. Elevated LDH concomitant with elevated alkaline phosphatase (AP) suggests malignant infiltration of the liver. Extrahepatic disorders that cause LDH elevation include hemolysis, rhabdomyolysis, tumor necrosis, renal infarction, acute stroke, and myocardial infarction.
