Objective:To investigate the relationship between serum creatine kinase level and histopathological observation of tubal ectopic pregnancy.Methods:Serum creatine kinase was determined by N-acetyl cysteine(NAC) assay in 22 patients with ruptured tubal pregnancies and 35 patients with unruptured tubal pregnancies.Fallopian tube tissues were examined by histopathology.Results:The mean levels of serum creatine kinase in patients with ruptured tubal pregnancies were significantly higher than that in those with unruptured tubal pregnancies(154.2±63.7 IU/L vs 107.8±51.3 IU/L

P <0.01).Creatine kinase levels were higher in isthmic than ampullary ectopic pregnancies(167.3±45.7 IU/L vs 113.5±54.9 IU/L

P <0.05).The mean creatine kinase levels in unruptured tubal pregnancies with intraluminal trophoblastic growth were significantly lower than the levels in those with extraluminal and mixed trophoblastic growth (91.3±43.7 IU/L vs 128.5±39.4 IU/L

P <0.05).The cutoff value of creatine kinase to be used for the prediction of tubal rupture in ectopic pregnancy was 135 IU/L

which resulted in a sensitivity of 77.2% and specificity of 82.8%.Conclusion:Serum creatine kinase determination may help in discriminating ruptured tubal pregnancies from unruptured ones and prediction of tubal rupture in ectopic pregnancy.