A comparison of the use of Papanicolaou-stained cervical cytological smears with Gram-stained vaginal smears for the diagnosis of bacterial vaginosisin early pregnancy

Our objective is to compare the efficacy of using Papanicolaou (PAP)stained cervical cytology smears with a standardized method of interpreting Gram-s tained vaginal smears for the diagnosis of bacterial vaginosis (BV) in preg nancy. High vaginal smears were Gram-stained and examined by a single observer to characterize 3 grades of vaginal flora and diagnose BV. Cervical smears wer e PAP-stained and examined for characteristic patterns of vaginal flora inc luding evidence of BV by either a number of cytotechnicians or a single cyt opathologist. The results of the 2 methods were compared. Seven hundred and forty-seven women attending an antenatal clinic in a district general hosp ital who consented to have a smear of vaginal secretions and cervical cytol ogy in early pregnancy. The main outcome measure is the diagnosis of BV by different methods in a pregnant population. Compared with the Gram-stain method for the diagnosis of BV, there was good agreement between PAP-stain interpretation by a single observer but the ag reement was not as good with PAP-stain interpretation by multiple cytotechn icians. When the grades were consolidated to normal (grade I) and abnormal flora (grades II and III), compared to Gram-stained smears, PAP cytology un dertaken by several cytotechnicians had a sensitivity of 80.7% and a specif icity of 90.7%. The sensitivity and specificity increased to 87% and 97%, r espectively, when the PAP-stained smears were read by a single cytopatholog ist. Using kappa scores, only those readings made by a single cytopathologi st were reliable. The setting in a cytopathology laboratory comprises multiple cytotechnician s, so that PAP-stain analysis of vaginal smears for the diagnosis of BV is Likely to provide results which are less reliable than those obtained by Gr am staining. The latter should be the first choice and every effort should be made to set up this service.