Role of creatine phosphokinase as a diagnostic marker in tubal ectopic pregnancy

Ectopic pregnancy (EP) is still one of the leading preventable causes of maternal morbidity and mortality in the first trimester. Amidst the use of sensitive assays for β-HCG and high-definition ultrasonography for the identification of EP, the search for a more reliable and sensitive marker remains a challenge till date. Our aim was to determine the validity of creatine phosphokinase (CPK) and its isoenzyme (CPK-MB) in the prediction of tubal EP.

A prospective and comparative diagnostic accuracy study was conducted among 105 pregnant women in the first trimester who met the eligibility criteria in the Department of Obstetrics and Gynecology, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences (NEIGRIHMS). The study included 35 patients each with tubal EP (EP), abortive intrauterine pregnancy (AP), and normal intrauterine pregnancy (NP). CPK, CPK-MB, and β-HCG were measured among all the participants, and the participants were followed up longitudinally.

A total of 105 pregnant women were included. The mean CPK and CPK-MB levels were significantly higher among the women with EP when compared to NP (P < 0.05) and AP (P < 0.05) women; however, there was no significant difference between the NP and AP groups (P > 0.05). Moreover, the receiver operating characteristic (ROC) curve showed that both CPK and CPK-MB were good predictors of EP, with CPK (area under the curve [AUC] = 0.764) being a better predictor than CPK-MB (AUC: 0.650) in the diagnosis of EP.

Early diagnosis of EP allows appropriate and timely management, which would not only reduce mortality and morbidity associated with the condition but also enable preservation of fertility and improve future pregnancy outcome. Hence, the need of the hour is a reliable biochemical diagnostic marker for EP, such as CPK.