Validation of a simplified grading of Gram stained vaginal smears for use in genitourinary medicine clinics.
OBJECTIVE
To validate a simplified grading scheme for Gram stained smears of vaginal fluid for the diagnosis of bacterial vaginosis (BV) against the accepted "gold" standard of Amsel's composite criteria.


METHODS
Women attending genitourinary medicine (GUM) clinics, as part of a multicentre study, were diagnosed as having BV if three or more of the following criteria were present; homogeneous discharge, elevated vaginal pH, production of amines, and presence of "clue" cells. Women with less than three of the criteria were considered as normal. Simultaneously, smears were made of vaginal fluid and Gram stained and then assessed qualitatively as normal (grade I), intermediate (grade II), or consistent with BV (grade III). Two new grades were used, grade 0, epithelial cells only with no bacteria, and grade IV, Gram positive cocci only.


RESULTS
BV was diagnosed in 83/162 patient visits using the composite criteria, the remainder being regarded as normal. The majority of patients with BV had a smear assessed as grade III (80/83, 96%) and the majority of normal women had a smear assessed as grade I (normal, 48/79, 61%), giving a high sensitivity (97.5%), specificity (96%), and predictive value for a positive (94.1%) and negative (96%) test, kappa index = 0.91. Smears assessed as grade II were found predominantly (12/13) among patients diagnosed as normal, with less than three of the composite criteria. Grades 0 and IV were both only found among normal women.


CONCLUSIONS
This simplified assessment of Gram stained smears can be used as an alternative to Amsel's criteria and is more applicable for use in busy GUM clinics.
Ison
C A
CA
Department of Infectious Diseases and Microbiology, Faculty of Medicine, Imperial College, St Mary's Campus, London, UK. c.ison@ic.ac.uk
Hay
P E
PE
D001826:Body Fluids / Q000382:microbiology; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D012680:Sensitivity and Specificity; D014626:Vaginal Smears / Q000592:standards*; D016585:Vaginosis, Bacterial / Q000175:diagnosis* / Q000382:microbiology