Diagnostic significance of total creatine kinase and its isoform in tubal ectopic pregnancy

Aim: Tubal ectopic pregnancy (tEP) must be diagnosed as early as possible because it is one of the leading causes of pregnancy-related death in the first trimester. The aim of this study was to evaluate the diagnostic value of serum total creatine kinase (CK) and its isoforms in diagnosis of tEP.

Methods: The study included 32 tEP cases, and gestational age-matched intrauterine (IU) abortion and normal pregnancy cases (n = 31 each). Serum total CK and CK-MB fraction were measured by the principle of spectrophotometry and CK-MM fraction was calculated from the above parameters. Serum β-hCG was measured using chemiluminescent immunoassay. All study parameters were measured at the time of presentation.

Results: Serum β-hCG levels were significantly low in patients with both tEP and IU abortion than normal pregnancy. Women with tEP had higher concentrations of total CK, CK-MM and lower concentrations of CK-MB% compared to both gestational age-matched IU pregnancy controls and IU abortion. Receiver-operator characteristic analysis revealed that the optimal cut-off for total CK, CK-MM and CPK-MB% as predictors of ruptured EP were 147 IU/L, 135 IU/L and 10%, respectively, with the former two having higher specificity, and latter high sensitivity.

Conclusion: Estimation of CK and its CK isoenzyme fractions can aid in quick and accurate diagnosis of tEP.