RESUMO
OBJECTIVE: To determine the sensitivity, the specificity, and positive and negative predictive values of two laboratory methods used to diagnose bacterial vaginosis; Gram stain and the Gardnerella vaginalis culture, in comparison with the clinical sings of vaginal discharge; homogeneous secretion, pH > 4.7, positive amine test and the presence of clue cells. DESIGN: A prospective, comparative and crossover type. SETTING: This study was carried out in the Health Center "Dr. José Castro Villagrana" SSA, situated in Tlalpan, México City. From January, 1992 to July, 1996. PARTICIPANTS: 3,142 women, from 16 to 55 years old with cervicovaginitis diagnosis, without previous treatment and sexual active life history. RESULTS: By means of clinical criterion (33.1%), it was diagnosed 1,041 women with bacterial vaginosis. Statistical differences were not found between the culture and Gram stain in the presence or no-presence of bacterial vaginosis diagnosed by clinical criterion (p = 0.33) The clue cells were the best predictor of bacterial vaginosis. CONCLUSIONS: The differences between both methods analysed were minimal and they didn't have statistical value so that, it is proposed the Gram stain as diagnostic method of bacterial vaginosis based on factors like speed, reproductiveness and low cost.