Use of vaginal creatinine levels in detecting premature rupture of membranes

Abstract

Aim: Misdiagnosis is frequent in premature rupture of membranes (PROM) patients. The most accurate diagnosis of PROM requires reliable laboratory tests. Due to the lack of a gold-standard diagnostic method, many methods have been proposed in this regard. The aim of this study is to determine an easy diagnostic method in early membrane rupture and to determine the usability, reliability and cut-off values of vaginal creatinine measurements in the detection of PROM compared to vaginal placental alpha microglobulin-1 (PAMG-1) test.Methods: We designed a cross-sectional study. A total of 63 patients admitted to the Obstetrics and Gynecology Clinic of Samsun Ondokuz Mayıs University with suspected PROM between 15 November 2012 and 15 June 2013 were included in this study. Following anamnesis, all patients were vaginally subjected to PAMG-1 (AmniSure® ROM) test with sterile speculum and injected with 5 cc of saline into the vagina, and then, a 3 cc sample was retrieved with the same injector and put into a biochemistry tube. Immediately thereafter, the material was sent to the biochemistry laboratory, centrifuged and stored at -70 0C until all samples were studied. The patients were classified as PROM and non-PROM based on the positive or negative result of PAMG-1 test. Following this classification, the patients were also grouped as PROM and non-PROM according to their vaginal creatinine values.Results: The mean maternal age of our patients was 26.3 years in the PROM group and 28.8 years in the non-PROM group. The mean gestational weeks were 30.8 weeks in the PROM patients and 32.5 weeks in the non-PROM patients. Of 20 patients subjected to PAMG-1 test for PROM diagnosis, 17 were PAMG-1 and creatinine positive while 3 were PAMG-1 negative and creatinine positive. Of 43 patients subjected to PAMG-1 test, 42 were PAMG-1 negative while 1 was PAMG-1 positive and creatinine negative. Accordingly, vaginal creatinine was found to have 94.4% sensitivity, 93.3% specificity, 85% positive predictive value, and 97.7% negative predictive value in PROM diagnosis. The mean creatinine values in the PROM and non-PROM groups were 0.39 (0.31) mg/dl and 0.04 (0.10) mg/dl, respectively (p=0.05).Conclusion: Creatinine assessment in vaginal flushing fluid can be a cheaper, faster, easily accessible and highly accurate test with 94.4% sensitivity and 93.3% specificity in PROM diagnosis.