Objective: To study the value of hCG ratio of blood in peritoneal cavity versus venous blood (RPhCG/VhCG) in diagnosis of early ectopic pregnancy (EP).
Methods: From Mar. 2009 to Oct. 2012, 268 cases with EP (EP group) and 53 women with intrauterine pregnancy with haemoperitoneum (hIUP) (hIUP group) from International Peace Maternity and Child Health Hospital of Shanghai Jiaotong University School of Medicine, Shanghai 6th People Hospital and Shanghai Jiangwan Hospital were enrolled in this prospective study. The HCG of all subjective were measured in blood in peritonea cavity and venous blood, then calculate the ratio of RPhCG/VhCG. Scatter point analysis and ROC were used to differentiate EP, determine threshold of hIUP and evaluate the sensitivity, specificity and accuracy in diagnosis EP preoperatively.
Results: The mean RPhCG/VhCG of EP group was 4.35, which was significantly higher than 0.81 in hIUP group (P < 0.01). Scatter point analysis showed that the threshold value of RPhCG/VhCG between ectopic pregnancy and hIUP was 1.0. The overall sensitivity of RPhCG/VhCG in the diagnosis of EP was 98%, the specificity was 100%, the positive predictive value was 100% and the negtive predictive value was 93%.
Conclusion: RPhCG/VhCG > 1.0 could be used to diagnose and differentiate EP from hIUP accurately.