Interobserver variation in the interpretation of Nugent scoring method for diagnosis of bacterial vaginosis.

BACKGROUND & OBJECTIVES: Bacterial vaginosis (BV) is the most common form of vaginal infection and an important cause of morbidity in women of reproductive age. This study was carried out to examine the interobserver variation on interpretation of Nugent scoring method in the diagnosis of BV.

METHODS: This prospective study was conducted in a rural primary health care center of north India from May 2003 to April 2004 and included 601 married, sexually active women between 18-49 yr of age presented with self-reported symptoms of vaginal discharge and/or genital itching and/or genital burning. Specimens collected from the lateral wall of vagina were subjected to Gram staining and the microscope slide smears were examined by 3 independent observers. Each of the three observers scored and interpreted the slides for diagnosis of bacterial vaginosis using the Nugent method.

RESULTS: Complete agreement amongst the three observers was found in 76.2 per cent of cases. In 22.13 per cent cases, two observers were in agreement while interpretation of the slides were in complete disagreement only in 1.66 per cent of cases. The interrater reproducibility was found to be excellent between observers 1 and 3, while between observers 1 and 2, and 2 and 3 it was good to fair.

INTERPRETATION & CONCLUSIONS: Nugent scoring system appears to be a reliable and convenient method for laboratory evaluation of cases of bacterial vaginosis. At the same time, one must be aware of the factors that might lead to discrepant results.