Original Research

How reliable is self-testing for gonorrhea and chlamydia among men who have sex with men?

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Our study shows that patients who collected their own rectal and pharyngeal samples had test results that were of equal or better accuracy than those of clinical providers.




Background Recent studies have demonstrated a high prevalence of pharyngeal (P) and rectal (R) Neisseria gonorrhoeae (GC) and Chlamydia trachomatis (CT) infections among men who have sex with men (MSM). Guidelines by the Centers for Disease Control and Prevention recommend testing at least annually. But surveys of medical providers suggest that adherence to these guidelines is minimal as a result of limited time and staff. Because of these concerns, we evaluated the feasibility and accuracy of patient self-testing.

Methods Three-hundred seventy-four patients at a Washington, DC clinic who identified themselves as MSM and requested testing for sexually transmitted infections (STIs) participated in the study. Patients performed self-screening using the Gen-Probe APTIMA Combo 2 (AC2) kit after viewing written and pictorial instructions. Trained providers also screened patients. We randomized the order in which patients or providers performed testing.

Results Among those receiving specific tests, 8% of patients tested positive for R-GC, 9.3% for P-GC, 12.7% for R-CT, and 1.3% for P-CT. We performed McNemar tests, stratified by infection type and anatomic site to evaluate concordance. Self-administered testing was significantly better at identifying P-GC (discordant: 3%) and R-GC (discordant: 2.9%) (P≤.01), and had results similar to provider- administered testing for P-CT (discordant: 0.5%) and R-CT (discordant: 1.1%) detection.

Conclusions The equivalent or better detection rates for rectal and oral gonorrhea and chlamydia among patients suggest that patients are capable of performing their own screening for STIs, which may increase infection detection and treatment.

The prevalence of Neisseria gonorrhoeae (GC) and Chlamydia trachomatis (CT) infections among men who have sex with men (MSM) are common but unfortunately difficult to identify as a result of their anatomic location and lack of symptoms. In recent studies, 3.7% to 14.9% of MSM tested positive for GC, and 1.7% to 10.7% tested positive for CT on a first screening.1-4 Even more striking, however, was that many of these infections were extragenital and asymptomatic, with rectal GC infections 5 times more common than urethral in one study,3 and more than 80% of rectal GC and CT infections reportedly asymptomatic in another.2

Given the prevalence of undetected infection, the Centers for Disease Control and Prevention (CDC) recommends screening all sexually active MSM at least yearly for rectal GC and CT and pharyngeal GC infections in addition to urethral infections.5 However, research suggests that relatively few physicians follow these recommendations. In a survey of 3509 physicians, less than 14% reported screening their male patients for gonorrhea and chlamydia.6 In another survey, approximately one-third of providers reported not having enough staff to talk with patients about sexually transmitted infections (STIs) and testing, not having enough time in patient visits, and having difficulty keeping up with guidelines for caring for high-risk patients, including MSM.7

These studies raise concern that GC and CT infections will go undiagnosed; failure to detect these infections in MSM is particularly dangerous, given the STIs’ relationship to human immunodeficiency virus (HIV) transmission.8 Urethral GC infections have been shown to increase shedding of HIV in semen,9 and a recent study of MSM also demonstrated that having had multiple rectal GC or CT infections within a 2-year period made HIV seroconversion more likely.10

Due to the importance of identifying GC and CT infections and providers’ concerns about lack of time to do so, studies have explored the possibility of patient-administered testing, which has numerous potential benefits. It decreases the time that a health care provider has to spend on STI testing, and it could lead to screening of larger numbers of patients. It may also enable providers to reach patient populations that are often not appropriately screened, including MSM, prison inmates, homeless patients, drug users, adolescents, and patients in rural or disadvantaged areas.11-19

Comparisons of patient- and clinician-collected samples have yielded encouraging results about the ability of MSM to perform self-administered testing. There was 98% concordance between patient and provider results for rectal GC/CT swabs in one study.20 And another study found that self-collected rectal swabs had equivalent or better sensitivity and specificity for GC/CT detection than provider-collected swabs.21

Only one study has explored both pharyngeal and rectal self-testing of MSM patients, and it found that patient and provider results were concordant for 91.6% of rectal specimens and 93.6% of pharyngeal specimens. Most discordant cases involved patient-identified positives where the provider test was negative. The study authors considered these likely false positives; most occurred in patients who were positive for GC at another site, making cross-contamination probable.22 It is important to investigate further, however, because it is also possible that patients were identifying cases that providers missed.


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