vaginal microflora is not understood The high prevalence of the syndrome in sexually active women and in women attending STI clinics suggests that a wide range of epidemiologic and microbiologic factors may contribute to its pathogenesis Clinical Assessment The symptoms of bacterial vaginosis—malodor and discharge—are not distinctive and can resemble those of trichomonal infection A complaint of dysuria or pruritus goes against the diagnosis As many as half of women who have signs of vaginosis are asymptomatic The vaginal discharge is moderate or copious, grayish-white, and homogeneous On examination, the vulva, vagina, and cervix are not inflamed, but concomitant infection with trichomonas or gonococci can complicate this picture Compared with the composite Amsel criteria, the use of single tests (e.g., pH, clue cells, or whiff test alone) produces lower positive and negative predictive values for the diagnosis of bacterial vaginosis When a wet mount of vaginal discharge is examined, clue cells can be seen which are epithelial cells that are studded with large numbers of small bacteria giving them a granular appearance with shaggy borders ( Fig 92.2 ) The ratio of epithelial cells to polymorphonuclear leukocytes in the discharge is or higher Lactobacilli (long rods) are sparse Gram stain can be used to confirm the presence of clue cells and the scarcity of long gram-positive rods (lactobacilli) Because 35% to 55% of women without bacterial vaginosis have positive cultures for G vaginalis, culture is not a useful diagnostic test In addition, a rapid, antigen-based test has been developed to assess for bacterial vaginosis using a vaginal swab sample, similar to the rapid antigen test for T vaginalis This test has improved sensitivity and specificity over Gram stain but may not be widely available Trichomonal infection is the major diagnostic alternative for patients suspected of having bacterial vaginosis