SERUM LACTIC-DEHYDROGENASE IN THE DIFFERENTIAL-DIAGNOSIS OF ACUTE HEPATOCELLULAR INJURY

Acute hepatocellular injury, whether due to viral hepatitis, hepatic i schemia, or drug hepatotoxicity, results in elevated levels of serum a minotransferases (AST and ALT). Serum lactate dehydrogenase (LD) is re ported to be markedly elevated in ischemic hepatitis. Thus, comparison s of the degree of elevation of serum levels of LD, ALT, and AST may b e helpful in the differential diagnosis of acute liver injury. To stud y this, we reviewed serum enzyme patterns early in the course of acute liver injury in patients with acute viral hepatitis A and B (n = 51), ischemic hepatitis (n = 20), and acetaminophen injury (n = 26). All p atients had serum ALT and/or AST at least five times the upper limit o f normal. For a given ALT and AST level, LD was higher in ischemic hep atitis and acetaminophen injury than in viral hepatitis. The mean ALT/ LD ratio for acute viral hepatitis was 4.65, for ischemic hepatitis 0. 87, and for acetaminophen injury 1.46. Mean ALT/LD ratio for viral hep atitis was significantly higher (p < 0.0001) than for the other two gr oups combined. An ALT/LD ratio of 1.5 differentiated acute viral hepat itis from ischemic hepatitis and acetaminophen injury with a sensitivi ty of 94% and a specificity of 84%.