Clinical utility of measuring white blood cells on vaginal wet mount and endocervical gram stain for the prediction of chlamydial and gonococcal infections.
BACKGROUND
White blood cells on endocervical Gram stain and vaginal wet mount are frequently used to predict chlamydial and gonococcal infections. Previous studies provide conflicting evidence for the clinical utility of these tests.


OBJECTIVE
To evaluate the clinical utility of measuring white blood cells on vaginal wet mount and endocervical Gram stain for the prediction of chlamydial infection and gonorrhea.


METHODS
Women undergoing pelvic examinations at 10 county health department family planning and sexually transmitted disease clinics were tested for chlamydial infection by ligase chain reaction assay (n = 4550) and for gonorrhea by culture (n = 4402). Vaginal wet mount and endocervical Gram stains were performed in county laboratories at the time of examination.


RESULTS
The prevalences of chlamydial infection and gonorrhea were 8.8% and 3.2%, respectively. For detection of chlamydial or gonococcal infection, the likelihood ratio was 2.85 (95% CI, 2.10-3.87) for > 30 white blood cells on vaginal wet mount and 2.91 (95% CI, 2.07-4.09) for > 30 white blood cells on endocervical Gram stain. Similar results were seen for individual diagnoses either of chlamydial infection or of gonorrhea.


CONCLUSIONS
Vaginal wet mount and endocervical Gram stain white blood cells are useful for the presumptive diagnosis of chlamydial infection or gonorrhea only in settings with a relatively high prevalence of infection or when other predictors can increase the likelihood of infection.
Moore
S G
SG
Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, 27599-7400, USA.
Miller
W C
WC
Hoffman
I F
IF
Fox
K K
KK
Owen-O'Dowd
J
J
McPherson
J T
JT
Privette
A
A
Schmitz
J L
JL
Leone
P A
PA
D000328:Adult; D002584:Cervix Uteri / Q000166:cytology* / Q000382:microbiology / Q000473:pathology; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000453:epidemiology; D002692:Chlamydia trachomatis / Q000302:isolation & purification; D005260:Female; D006069:Gonorrhea / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D007958:Leukocyte Count / Q000592:standards*; D009344:Neisseria gonorrhoeae / Q000302:isolation & purification; D009657:North Carolina / Q000453:epidemiology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014621:Vagina / Q000166:cytology* / Q000382:microbiology / Q000473:pathology