Agreement Between Serum Creatine Phosphokinase and Transvaginal Ultrasound in Diagnosis of Ectopic Pregnancy: Cross Sectional Study

Objective:
To determine agreement between serum creatine phosphokinase (CPK) and transvaginal ultrasound (TVS) in diagnosis of ectopic pregnancy. To see the possible clinical role of serum creatine phosphokinase compared to standard markers like β-hCG.
Method:
In this cross-sectional study a total of 70 female participants were recruited. The age of the participants were 15-45 years with gestational amenorrhea of 8-10 weeks and with the clinical suspicion of ectopic pregnancy. Serum creatine phosphokinase levels were measured in all participants, and transvaginal ultrasound was used as the main diagnostic test to determine the presence of absence of ectopic pregnancy. The Kappa statistics were used to evaluate the level of agreement between serum creatine phosphokinase and transvaginal ultrasound.
Results:
Using CPK levels, 30 females (42.9%) were identified as having ectopic pregnancy, while TVS detected 27 women (38.6%). When both tests were compared, 61 out of 70 cases (87.1%) showed the same result either both positive or both negative. The results indicate a significant agreement (Kappa = 0.734, p < 0.001).
Conclusion:
Serum CPK levels (>145 U/L) showed a strong correlation with TVS in diagnosing ectopic pregnancy. This suggests that CPK may serve as a supportive tool, especially in settings with limited ultrasound access. However, TVS should remain the gold standard for definitive diagnosis. Furthermore, Larger multicenter trials are required before serum creatine phosphokinase can be considered for routine clinical use.

Ectopic pregnancy, transvaginal ultrasound, creatine phosphokinase, diagnostic accuracy.