Objective-To compare the occurrence of Trichomonas vaginalis as demons
trated by culture and by Papanicolaou (PAP) smears in a sexually trans
mitted disease (STD) clinic. Setting-The largest out-patient venereolo
gical clinic in Denmark. Subject and methods-As the prevalence of tric
homonal infestation has decreased considerable in recent years direct
microscopy of vaginal wet mounts is no longer performed routinely. Ins
tead the screening diagnostic procedure is based on culture. We have r
etrospectively collected data on culture-negative women with Trichomon
as vaginalis organisms present in cervical smears, taken on a routine
basis to exclude atypical cells, and compared with the clinical findin
gs.Results-Since 1992 a total of 17 women were found to harbour Tricho
monas vaginalis in cervical smear. A vaginal discharge was described i
n 10 women, six of whom had concomittant unspecific vaginitis. However
, four women had unexplained vaginal discharge that could have been re
lated to infestation with Trichomonas vaginalis. In addition one asymp
tomatic woman had a male partner with persistent urethritis. Conclusio
n-The prevalence of trichomoniasis is underestimated in women attendin
g the clinic if the diagnosis is based on culture alone. PAP smears ma
y be helpful in demonstrating characteristic trichomonal organisms. In
general we do not recommend the PAP smear be used to diagnose STDs. H
owever the finding of trichomanal organisms in smears should prompt a
repeated culture and direct microscopy of vaginal wet mount.