Diagnostic power of one-step beta human chorionic gonadotropin (ßHCG) test strips in detecting premature rupture of membranes

With respect to the prevalence and complications of premature rupture of chorionic membranes (PROM) and the importance of correct and on-time detection of the disorder with false positive or negative results, accurate as well as noninvasive diagnostic procedures are always needed.This case-control study was conducted to identify the diagnostic power of qualitative evaluation of beta human chorionic gonadotropins (ßHCG) in cervicovaginal discharge with 1-step test strips (25 IU/ml) for detecting PROM in women referring to Vali-e-Asr Hospital at Zanjan city in 2007. 86 singletons between 14 and 41 weeks of gestation were selected. Data collection tools included a form for demographic information as well as gestational history and an observation checklist for speculum examination and tests of Fern, nitrazine and qualitative strip for ßHCG. Of women with amniotic fluid leakage, subjects were examined in 2 43-person groups including those with definite PROM (direct observation with speculum [+], Fern test [+] and nitrazine test [+]) in case group and those with intact membranes (direct observation with speculum [-], Fern test [-] and nitrazine test [-]) in control group. Subjects were matched in terms of gestational weeks in the two groups. Cervicovaginal discharge samples were taken by rinsing posterior fornix with 5ml saline and aspiration of fluid. ßHCGs were then tested by 1-step gestational strips. It was found that sensitivity, specificity, positive as well as negative predictive values and accuracy of the strips were 97.7%, 88.4%, 89.4%, 97.5% and 93%. It seems that the diagnostic power of qualitative evaluation of ßHCGs in cervicovaginal discharge to detect PROM is acceptable.