Alanine Aminotransferase (ALT/SGPT)

A liver function test, ALT is more sensitive for the detection of hepatocyte injury than for biliary obstruction. ALT is more specific for liver injury than AST (SGOT). Useful for hepatic cirrhosis, other liver disease. Increased in Reye syndrome, with AST.¹ Test for hepatitis. Acute hepatitis A or B can be confirmed serologically, as can hepatitis C. Negative serological findings in the presence of hepatitis-like chemistry abnormalities may also suggest acute drug-induced hepatitis, an impression supported by resolution after removal of the offending agent.² The combination of increased AST and ALT with negative hepatitis markers occurs in a number of other entities including infectious mononucleosis. Sensitive to heart failure.

Grossly hemolyzed samples can generate somewhat spurious results. The activity in red cells is six times that of serum. Elevations are reported in trauma to striated muscle, rhabdomyolysis, polymyositis and dermatomyositis, but the CK (CK-MM fraction) is increased in such patients and it is preferable to consider diseases of skeletal muscle. ALT is less sensitive than is AST to alcoholic liver disease. Increased ALT is found with obesity.

Kinetic

Among entities in which AST and ALT increases occur, are therapeutic applications of bovine or porcine heparin. LD (LDH) abnormality with elevation of hepatic fractions was also reported.³ In children with acute lymphoblastic leukemia, high ALT activity at diagnosis is associated with rapidly progressive ALL.⁴ A number of drugs, including diphenylhydantoin, heparin therapy and many others, cause ALT increases. Acetaminophen hepatotoxicity may be potentiated in alcoholics, in whom coagulopathy and extremely abnormal aminotransferase levels are described, ALT less than AST.⁵ The hepatitis C virion has been detected by polymerase chain reaction and reverse transcriptase of HCV-RNA sequences in patients with elevated ALT and positive anti-HCV.⁶