Efficacy of self-collected pharyngeal swabs to detect chlamydia and gonorrhea in a non-clinic setting

Background: Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) are two of the most common reportable infectious diseases in the US and can increase the risk of HIV infection. The purpose of this study is to determine the efficacy and acceptability of self-collected pharyngeal swabs to detect CT and GC and to establish the prevalence of pharyngeal infections in a non-clinic community-based testing center in Salt Lake City, Utah.

Methods: A total of 201 participants were recruited from March 2013 to August 2013 from the Utah AIDS Foundation HIV/STI testing center. Both a clinician-collected and self-collected pharyngeal swab were obtained from each participant. Kappa statistic was used to determine percent agreement between clinician-collected and self-collected swabs. Acceptability was analyzed from responses to a six-question Likert-scale survey using an ordinal logistic regression model.

Results: Prevalence of pharyngeal CT and GC infection was 3.5% (7/201) and 3.0% (6/201), respectively. Percent agreement between clinician-collected and self-collected swabs was 99.5% for CT with a kappa of 0.92 (95% CI: 0.77-1.0) and 99.5% for GC with a kappa of 0.91 (95% CI: 0.72-1.0). Acceptability was high among all participants.

Conclusion: Self-collected pharyngeal swabs are acceptable among men and women and have a high efficacy of CT and GC detection in non-clinic settings. Self-collection methods provide increased access to testing in non-traditional settings such as: community organizations; internet, phone, and mail-order testing; and over-the-counter testing. Routine testing is recommended for all sexually active individuals, including “low-risk” sexually-active individuals who report fellatio as their sole risk factor.