Nonutility of measurement of serum gamma-glutamyl transpeptidase activities in diagnosis of myocardial disease.

We have examined the usefulness of measuring gamma-glutamyl transpeptidase activity in serum, in diagnosing myocardial damage. Abnormalities in gamma-glutamyl transpeptidase activity were compared with those observed for aspartate aminotransferase, lactate dehydrogenase isoenzymes, creatine kinase, alanine aminotransferase, and alkaline phosphatase. Such measurements were made for 12 consecutive days on 22 patients admitted to the coronary care units. Serum gamma-glutamyl transpeptidase activity was not increased in all cases studied, but when it was increased, the electrophoretic band of the lactate dehydrogenase isoenzyme originating from the liver also showed abnormal activity. We conclude that the changes observed in gamma-glutamyl transpeptidase activity primarily reflect liver involvement, as in congestive heart failure, rather than myocardial disease.