evaluation of serum creatine phosphokinase in diagnosis of tubal ectopic pregnancy compared with intrauterine pregnancy and threatened abortion

background: vaginal sonograghy and serial -hcg are the most common diagnostic methods for ectopic pregnancy but about 50% of cases are initially misdiagnosed. in tubal pregnancy the zygote lies next to the muscular layer, and this invasion causes an increase in creatine phosphokinase (cpk) in blood. objective: assessment of cpk and its isoenzyme cpk-mb as a diagnostic marker for tubal pregnancy. materials and methods: in this case-control study, 111 women between 16-40 years in first-trimester pregnancy admitted to emergency ward of rasht alzahra hospital with abdominal pain or vaginal bleeding were included and according to sonography and βhcg divided into 3 groups (n=37): tubal pregnancy (1), threatened abortion (2) and normal pregnancy (3). blood samples were taken for totalcpk and cpk-mb before any invasive procedure. results: mean total cpk level were 96.27±63.9 u/lit (group 1), 55.37±14.1 u/lit (group 2) and 48.94±19.2 u/lit (group 3) and was significantly higher in tubal pregnancy compared to other groups. mean cpk-mb levels in 3 groups were 15.62±5.2 u/lit, 17.32±6.9 u/lit, and 15.1±4.7 u/lit, respectively which was not significant. conclusion: it seems that determination of total cpk can enhance the diagnostic value of tubal pregnancy.