Good performance of rapid prostate-specific antigen test for detection of semen exposure in women: implications for qualitative research.
BACKGROUND
Prostate-specific antigen (PSA) is a valid biomarker of semen exposure in women and has been used to assess reliability of self-reported sexual behavior as well as serve as a proxy measure for condom efficacy. Quantitative PSA tests are expensive and require specialized equipment. A simple, rapid, and inexpensive test for PSA would facilitate semen biomarker evaluation in a variety of research settings. This study evaluated the performance of a rapid PSA test compared with a quantitative assay to identify semen in vaginal swab specimens.


METHODS
We tested 581 vaginal swabs collected from 492 women participating in 2 separate research studies in Bangladesh and Zimbabwe. PSA in vaginal secretions was detected using the quantitative IMx (Abbott Laboratories) assay and the ABAcard p30 (Abacus Diagnostics) rapid immunochromatographic strip test.


RESULTS
The ABAcard test was 100% sensitive (95% confidence interval [CI], 98%-100%) and 96% specific (95% CI, 93%-97%) compared with the quantitative test in detecting >1.0 ng PSA/mL vaginal swab eluate. Rapid PSA results were semiquantitative and correlated well with PSA concentrations (kappa = 0.88; 95% CI, 0.85-0.90).


CONCLUSIONS
Rapid PSA detection requires no instrumentation and can be performed easily and economically. Having rapid PSA results available immediately following interview provides opportunities to explore discrepancies between the objective marker of recent semen exposure and self-reported behaviors.
Hobbs
Marcia M
MM
Department of Medicine, University of North Carolina at Chapel Hill, CB# 7031, Chapel Hill, North Carolina 27599, USA. mmhobbs@med.unc.edu
Steiner
Markus J
MJ
Rich
Kimberly D
KD
Gallo
Maria F
MF
Alam
Anadil
A
Rahman
Motiur
M
Menezes
Prema
P
Chipato
Tsungai
T
Warner
Lee
L
Macaluso
Maurizio
M
D001459:Bangladesh; D015415:Biomarkers / Q000032:analysis*; D002845:Chromatography / Q000379:methods; D017280:Condoms / Q000706:statistics & numerical data; D004868:Equipment Failure; D005260:Female; D006801:Humans; D007158:Immunologic Techniques; D008297:Male; D017430:Prostate-Specific Antigen / Q000032:analysis*; D036301:Qualitative Research; D011933:Reagent Kits, Diagnostic; D011934:Reagent Strips / Q000032:analysis; D012661:Semen / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D013997:Time Factors; D014621:Vagina / Q000737:chemistry*; D015030:Zimbabwe
D015415:Biomarkers; D011933:Reagent Kits, Diagnostic; D011934:Reagent Strips; D017430:Prostate-Specific Antigen