Creatine phosphokinase in ectopic pregnancy revisited: Significant diagnostic value of its MB and MM isoenzyme fractions

Objective Although evidence on elevated creatine phosphokinase (CPK) as a tool for the diagnosis of ectopic pregnancy (EP) is rather conflictive, no previous study on CPK isoenzyme levels and their relative ratio was found in the literature. Study design Forty women with EP, 20 with intrauterine (IU) abortive gestation, and 20 regular pregnant women (controls) were studied. Serum total CPK, CPK-MB, and CPK-MM levels were measured at the time of presentation and 24 hours after surgery. Relative operating characteristic (ROC) curves were plotted. Results Women with EP had significantly higher CPK concentrations and a significantly decreased CPK-MB relative ratio (CPK-MB%), compared with both women with IU abortive pregnancy and controls. The ROC curves demonstrated a significant discriminatory ability of both increased total CPK and decreased CPK-MB% ratio for the diagnosis of EP. Conclusion Determination of CPK isoenzyme fractions can significantly enhance the diagnostic value of total maternal CPK in the prediction of ectopic pregnancy.