Diagnostic value of clinical examination, direct microscopy, and culture in the Gardnerella vaginalis syndrome.

In a general practice 467 women aged 15-49 years with vaginal discharge were consecutively examined in order to compare the diagnostic value in the Gardnerella vaginalis syndrome of the clinical examination, direct microscopy of the vaginal secretion, and culture. We found significant correlations between all relevant combinations of the diagnostic methods. The predictive value of a positive test for the clinical examination, the microscopy, and the clinical examination combined with microscopy, respectively, was 0.75, 0.89 and 0.90, whereas the predictive values of the negative test were 0.59, 0.72 and 0.61, respectively. Because even small numbers of Gardnerella vaginalis may yield growth on selective culture media, the clinical examination and the microscopy are often negative despite positive culture. To avoid overtreatment of a benign condition we therefore conclude that the presence of a characteristic clinical picture and positive microscopy constitute a safe basis for the diagnosis of the Gardnerella vaginalis syndrome, and that the diagnosis should be based on this combination or on the fulfilment of three of the following four criteria: 1) characteristic vaginal secretion; 2) vaginal pH greater than 4.5; 3) positive potassium hydroxide test or characteristic herring-brine smell, and 4) clue cells at microscopy. With the present methods culture for Gardnerella vaginalis should not routinely be performed, until the value of quantitated methods has been proved. Coexistence of other microorganisms rendered the diagnosis difficult. We recommend to treat the most predominant infection first.