Objective. To evaluate the sensitivity and specificity of the score and each one of the clinical criteria (pH, potassium hydroxide (KOH) test for amines, and clue cells) in relation to the Amsel's method.
Materials and Methods. One hundred ninety vaginal exudates from pregnant women were studied from April to August 1997. The patients were examined in the Lower Genital Tract and Colposcopy Clinics of the Obstetrics Division at the University Hospital de Clínicas at the University of Buenos Aires, Argentina.
The diagnosis of bacterial vaginosis (BV) was made by the presence of three or more of the following criteria: homogeneous vaginal discharge, pH ≥ 4.5, positive KOH test for amines, and microscopic presence of clue cells. We also used the microscopic observation of coccobacilli forms in Gram stain (Nugent's method), diagnosing BV with a score ≥ 7.
Results. Nugent's method showed a sensitivity of 97% and specificity of 98%. The presence of clue cells showed a sensitivity of 92% and specificity of 97%. The sensitivity of the pH and KOH test for amines was 87% and 81%, whereas the respective specificity was 45% and 99%.
Conclusions. Because Nugent's method showed a very good specificity and sensitivity, it can be used as another method in the diagnosis of BV. The presence of clue cells diagnosed BV with better sensitivity and specificity than the other clinical criteria. In this way, we recommend the microscopic exam by Gram stain, using Nugent's method or the presence of clue cells, for diagnosing BV.