This glycolytic enzyme is increased in a number of skeletal muscle conditions, including progressive Duchenne’s muscular dystrophy (including carriers), dermatomyositis, polymyositis, limb-girdle dystrophy, myotonia dystrophy, and rhabdomyolysis. Normal values are seen in neurogenic atrophies. Elevated levels have been found in acute hepatitis, myocardial infarction, hemorrhagic pancreatitis, trichinosis, gangrene, prostatic tumors, carcinomas metastatic to the liver, granulocytic and megaloblastic anemias, delirium tremens, 60% to 80% of patients with acute psychoses and schizophrenia, and neoplasia. In recent years the assay of creatine kinase (CK) has replaced the assay of aldolase activity in serum, especially in muscular dystrophy. In acute viral hepatitis, increases tend to parallel ALT.