Variability of vaginal pH determination by patients and clinicians.
OBJECTIVE
Measurement of intravaginal pH provides a reasonable assessment of vaginal health but is fraught with the potential for several sampling errors. The purposes of the study were to determine the variability of self-sampled vaginal pH among women using an inexpensive swab-based pH test compared with a clinician-obtained specimen, and variability of vaginal pH within 3 regions of the normal vagina.


METHODS
In this cross-sectional study, women obtained a vaginal specimen using a cotton-tip applicator, transferred it to pH paper, and interpreted the results. A clinician also blindly interpreted these tests. Thereafter, a clinician obtained 3 swab specimens from the proximal, middle, and distal vagina for pH testing. Results were compared using Wilcoxon signed rank test, interclass correlation coefficients, Bland-Altman plots, and mixed-model analysis of variance.


RESULTS
Interclass correlation coefficients were moderately high comparing subjects with clinician for the swab-based pH test (0.74). Subjects' swab pH values (4.5) were significantly lower than clinicians' pH values (4.7, P = .0001). Intravaginal pH did not vary between the 3 anatomic locations.


CONCLUSIONS
Self-sampled intravaginal pH interpretations vary slightly compared with clinician-obtained specimens. Because swab pH sampling does not detect an intravaginal pH gradient in normal women, self-sampling technique may vary considerably without affecting outcomes. Our findings support self-sampling for vaginal pH before using over-the-counter products for presumed vaginitis.
Ferris
Daron G
DG
Department of Family Medicine, The Medical College of Georgia, Augusta, GA 30912, USA. dferris@mcg.edu
Francis
Sean L
SL
Dickman
Eileen D
ED
Miler-Miles
Kimberly
K
Waller
Jennifer L
JL
McClendon
Nora
N
D000293:Adolescent; D000328:Adult; D001294:Attitude to Health; D003430:Cross-Sectional Studies; D005260:Female; D006282:Health Personnel; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010361:Patients; D012648:Self Care; D020377:Self Efficacy; D013997:Time Factors; D014621:Vagina / Q000502:physiology*; D014627:Vaginitis / Q000175:diagnosis; D055815:Young Adult