Performance and acceptability of self-collected specimens for diagnosis of rectal and pharyngeal Chlamydia trachomatis and Neisseria gonorrhoeae infections among men who have sex with men in China: a randomized controlled trial.

BACKGROUND

Extragenital Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections are prevalent among men who have sex with men (MSM). Self-sampling could potentially eliminate barriers to extragenital CT/NG testing for MSM that are hard to reach, who refuse to go for clinician-based testing, or who decline an examination. However, the required evidence to determine whether self-collected specimens are as accurate as clinician-taken specimens in terms of CT/NG diagnostic accuracy was limited in low and middle income countries. We therefore compared self-collected rectal and pharyngeal specimens with clinician-taken specimens for diagnostic accuracy among MSM in China.

METHODS

This was a prospective convenience sample from 6 sexually transmitted infection (STI) clinics in China. We randomized the order of self-collected and clinician-taken specimens from the pharynx and rectum, plus first-void urine, for CT/NG detection. Self-sampling performance was compared with clinician-sampling as to agreement, sensitivity, and specificity. The acceptability of self-sampling was evaluated by questionnaire.

RESULTS

Among the 325 participants, prevalences of rectal CT and NG infections were 13.6% and 5.2% and pharyngeal CT and NG prevalences were 1.5% and 2.8%, respectively. The agreements between the CT tests with the self-collected and clinician-taken specimens were 98.8% (κ = 0.95, 95% CI 0.89-1.00) for rectal site and 99.4% (κ = 0.83, 95% CI 0.60-1.00) for pharyngeal site; and the agreements between NG tests were 99.4% (κ = 0.94, 95% CI 0.86-1.00) for rectal site and 98.2% (κ = 0.72, 95% CI 0.50-0.93) for pharyngeal site. The sensitivity and specificity of self-collected swabs was as follows: rectal CT: 93.0% and 99.6%; pharyngeal CT: 100.0% and 99.4%; rectal NG: 100.0% and 99.4%; pharyngeal NG: 88.9% and 98.4%. Self-collection was highly acceptable, showing that 62.0% MSM preferred self-sampling over clinician-sampling; 90.2% would use self-sampling for detection of CT and NG again.

CONCLUSIONS

Extragenital screening for CT and NG should be recommended as part of STI services to MSM population. Self-collection of rectal and pharyngeal specimens had good performance for CT and NG tests and acceptability to the target population.

TRIAL REGISTRATION

This trial was registered with the Chinese Clinical Trial Registry, ChiCTR2300073473. Registered 12/07/2023.