Comparison of clinical criteria and laboratory criteria used for the diagnosis of bacterial vaginosis

Abstract

OBJECTIVES: To determine the prevalence of BV among women who present with vaginal discharge.To determine the usefulness of Amsel's clinics' criteria to diagnose BV by comparing it with the Nugent criteria, which is the gold standard. METHODOLOGY: 300 patients who presented with vaginal discharge to the sexually transmitted diseases (STD) clinic, gynecology clinics and gynecology wards at North Colombo Teaching Hospital,Ragama and STD clinic -Colombo, between 1 st January 2011 to 30th April 2011 were included in the study Four high vaginal swabs were collected during the speculum examination and examined according to the Amsel's and Nugent's criteria. Appearance of the vaginal discharge was observed. RESULTS: The prevalence of BV among women who presented with vaginal discharge was 25.3% (76/300) by the Nugent's method. Among the women with vaginal discharge BV was diagnosed more in STD group which is 33.8% (52/ 154) compared to the non STD group which is 16.4% (24/146). The sensitivity, specificity, positive and negative predictive values were calculated to assess the validity of the Amsel's method considering the Nugent's criteria as the goid standard. Diagnosis of BV by performing Amsel's method exhibit a low sensitivity (55.3%) and high proportion of false positives (positive predictive value-59.2%) when compared against Nugent's method. CONCLUSIONS: The Amsel's method is not a satisfactory method to be used as a diagnostic tesffor BV. At present BV is diagnosed by examining the nature of vaginal discharge or by using some of the Amsel's criteria. As we have found that Amsel's criteria cannot diagnose BV satisfactorily, we have to establish Nugent's method to diagnose BV in Sri Lanka.