An Isolated AST Elevation due to Macroenzyme Formation / 대한간학회지

ABSTRACT

Serum aspartate aminotransferase (AST) is a common enzyme for the evaluation of the hepatic, muscular and cardiac diseases and is produced also at kidney, brain, pancreas, lung, leukocytes, erythrocytes, etc. The elevation of its activity is usually caused by the necrosis of hepatocytes when there are not muscular injuries or myopathies. Recently, it is found that AST can exist as a macroenzyme by forming a complex with an immunoglobulin and this complex is erroneously considered to indicate the presence of liver disease as a result of elevation of AST activity on routine blood chemistry analysis. We experienced the patient with isolated AST elevation due to the formation of AST-mmunoglobulin complex confirmed by AST isoenzyme electrophoresis (EP).