Comparison Of Different Methods For The Diagnostic Value Of Bacterial Vaginosis

Objective:It helps diagnosis and treatment of bacterial vaginosis by comparison of sensitivity, specificity, positive predictive value, negative predictive value and the reliability among three test methods including gardnerella vaginalis kits( hereinafter referred to as an immunofluorescence method), vaginal micro-ecological evaluation system and Amsel criteria. Objects of study:465 patients aged 20 to 60 year-old who came from a gynecological out-patients clinic were enrolled from October, 2015 to December, 2015 in the second hospital of Jilin university. Among them, 331 patients had the symptoms of vaginitis including vulvar discomfort, the amount and characteristics of vaginal discharge, vaginal odor and so on. 134 patients had no symptoms of vaginitis. The clinic data of these patients were recorded in detail. Results:1. Comparison of three methods’ positive rates in BV diagnosis: Amsel criteria was 22.8%, immunofluorescence method was 51.8%, vaginal micro-ecological evaluation system was 21.7%. By the chi-square test, the difference was statistically significant. The positive rates of three test methods were ranked from high to low: immunofluorescence method, Amsel criteria, vaginal micro-ecological evaluation system.2. The sensitivity, specificity, positive predictive value( PPV), negative predictive value( NPV) of three test methods: according to the area under the Roc curve show all have diagnostic value. The AUC of Amsel criteria was 0.945, which indicated that it had higher accuracy. The AUC of vaginal micro-ecological evaluation system was 0.890. The AUC of immunofluorescence method was 0.745.The sensitivity of three test methods were short of 90%. The specificity of Amsel criteria and positive predictive value were 100%, negative predictive value is up to 96%.The specificity, positive predictive value and negative predictive value of vaginal micro-ecological evaluation system was 98%, 94% and 93%, respectively. The specificity and positive predictive value of immunofluorescence method( 61% and 44%, respectively.), negative predictive value was higher( 94%). The reliability of Amsel criteria and vaginal micro-ecological evaluation system was greater than 0.75, which showed that they were more reliable. The reliability of immunofluorescence method was less than 0.4, which declared that its reliability was low.3. According to the diagnostic criteria, we can calculate sensitivity, specificity, positive predictive value( PPV) and negative predictive value( NPV) of the Amsel criteria. The area under the ROC curve( AUC) of clue cells and amine test were 0.866 and 0.728, respectively. It indicated that clue cells and amine test had certain accuracy. The specificity value of clue cells was the highest( 100%), amine test came second( 92%).However, the sensitivity value of clue cells and amine test was lower(21%, 54%, respectively). Positive predictive value( PPV) of clue cells was 100%, but its negative predictive value( NPV) was simply 52%. The AUC of vaginal discharge and PH value were 0.589 and 0.694, which indicated that they had lower accuracy.4. The area under the ROC curve( AUC) of immunofluorescence method combined with PH value or amine test or vaginal discharge or clue cells was from 0.7 to 0.9, which indicated that four combined methods had certain accuracy. Compared with immunofluorescence method alone: the specificity values of four combined methods were not improved, the specificity values of immunofluorescence method combined with amine test or clue cells significantly improved( 96% and 100%, respectively), the specificity values of immunofluorescence method combined PH value or vaginal discharge were lower. Kappa values of four combined methods were less than 0.75, which declared immunofluorescence method combined with PH value or amine test or vaginal discharge or clue cells can’t get good consistency yet. Conclusion:1. Positive rates of immunofluorescence method, vaginal micro-ecological evaluation system and Amsel criteria in BV diagnosis were significantly different. Immunofluorescence method’s positive rate was highest, the accuracy was worse and its specificity was lowest. These evidences indicated that misdiagnosis rate was high by immunofluorescence method diagnosed BV.2. Among four items in Amsel criteria, clue cells’ specificity was highest, so it had certain accuracy for the diagnosis of BV. But its sensitivity was lowest, the risk of missed diagnosis increased.3. Immunofluorescence method combined with clue cells can increase the diagnostic accuracy and reduce misdiagnosis risk, but its accuracy was significantly lower than Amsel criteria and vaginal micro-ecological evaluation system.4.The accuracy of vaginal micro-ecological evaluation system and Amsel criteria to diagnose BV was higher, but vaginal micro-ecological evaluation system would combine morphology with enzymology, in this way, we can detect the change of vaginal micro-ecology. Thus, recently, vaginal micro-ecological evaluation system would be likely to become a first choice that can rapidly diagnose the common vaginitis in clinic.