To examine the agreement between sexually transmitted infection (STI) screening using self-collected specimens and physician-collected specimens, and to investigate the acceptability of self-collection for screening in an 18-month study of female sex-workers (FSW) in a high-risk, low-resource setting.
A total of 350 FSW in Nairobi, Kenya participated in a prospective study from 2009-2011. Women self-collected a cervico-vaginal specimen. Next, a physician conducted a pelvic examination to obtain a cervical specimen. Physician- and self-collected specimens were tested for Chlamydia trachomatis (CT), Neisseria gonorrhoeae (GC), Trichomonas vaginalis (TV) and Mycoplasma genitalium (MG) using Aptima nucleic acid amplification assays (Hologic). Specimens were collected at three-month intervals over 18-months follow-up. Kappa statistics measured agreement of positivity between self- and physician-collection.
Baseline STI prevalence was 2.9% for GC, 5.2% for CT, 9.2% for TV, and 20.1% for MG in self-collected samples, and 2.3%, 3.7%, 7.2%, and 12.9% respectively in physician-collected samples. Kappa agreement was consistently strong (range 0.66-1.00) for all STIs over the 18-month study period, except MG which had moderate agreement (range: 0.50-0.75). Most participants found self-collection easy (94%) and comfortable (89%) at baseline, with responses becoming modestly more favorable over time.
Self-collected specimens screening results showed strong agreement to clinical-collected specimens, except MG which was consistently detected more commonly in self- than physician-collected specimens. Acceptability of the self-collection procedure was high at baseline and increased modestly over time. In high-risk, low-resource settings, STI screening with self-collected specimens provides a reliable and acceptable alternative to screening with physician-collected specimens.
1Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, North Carolina
2Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, North Carolina
3Department of Clinical Pharmacy, University of California, San Francisco, California
4Department of Obstetrics and Gynecology, Thomas Jefferson University, Philadelphia, Pennsylvania
5Kenyatta National Hospital/University of Nairobi, Nairobi, Kenya
6Lineberger Cancer Center, University of North Carolina at Chapel Hill, North Carolina
Corresponding author: Jennifer S. Smith PhD, MPH. Professor, Department of Epidemiology, Campus Box 7435, University of North Carolina in Chapel Hill, Chapel Hill, North Carolina, 27599. Email: JenniferS@unc.edu