Publication

The impact of including throat and rectal swabs for chlamydia and gonorrhea testing online in British Columbia, Canada

Aidan Ablona, Troy Grennan, Trevor Hart, Jean Shoveller, Joseph Cox, Gina Ogilvie, Mel Krajden, Christopher Fairley, Devon Haag, Mark Gilbert

STI & HIV World Congress, July 14-17, 2019

Background: GetCheckedOnline (GCO) is a comprehensive, online sexually-transmitted infection (STI) testing service in British Columbia, Canada, which includes urine nucleic acid amplification testing (NAAT) for chlamydia (CT) and gonorrhea (GC). In 2016, responding to mounting evidence of missed infections with urine-only screening, self-collected throat and rectal swabs were added. We aimed to describe missed infections with urine-only screening.

Methods: We retrospectively analyzed all CT/GC-related testing episodes conducted through GCO in 2016-2018Urine testing is recommended for all GCO clients. Rectal swabs are recommended to clients reporting receptive anal sex in the past 3 months; throat swabs are recommended to men who have sex with men (MSM) who indicate giving oral sex in the past 3 months. We described prevalence by site and quantified the proportion of CT/GC infections missed with urine-only screening.

Results: Of 10,724 CT/GC urine test episodes, 2746 (25.6%) and 2288 (21.3%) included throat and rectal swabs, respectively. 95.0% and 86.0% of clients recommended for throat and rectal swab testing submitted samples, respectively.

Among women, 3760 CT/GC urine test episodes were conducted, with 560 (14.9%) including rectal swabs. Percent positivity by infection-site was 3.6% CT-urine, 3.0% CT-rectal, 0.1% GC-urine, and 0.2% GC-rectal. Urine testing alone detected 95.3% of CT/GC infections.

Among MSM, 3088 CT/GC urine test episodes were conducted, with 2587 (83.8%) including throat swabs and 1635 (52.9%) including rectal swabs. Percent positivity by infection-site was 1.5% CT-urine, 0.7% CT-throat, 5.1% CT-rectal, 0.5% GC-urine, 2.4% GC-throat, and 2.8% GC-rectal. Urine testing alone detected only 25.4% of all CT/GC infections.

Conclusion: The majority of GCO clients recommended for self-collected throat and rectal swabs submitted samples. Approximately three-quarters of CT/GC infections among MSM would have been missed if swabs had not been offered. Online STI testing services should provide comprehensive biospecimen collection when indicated to facilitate CT/GC detection and treatment.