Promising approach to improve testing coverage for chlamydia and gonorrhoea

The WHO commissioned Eric Chow (left) and Jason Ong (right) to
 review alternative methods of STI testing from molecular methods.

The World Health Organization (WHO) estimates that more than 1 million new cases of curable sexually transmitted infections (STIs) are acquired every day. 

As most STIs do not present with any symptoms, screening is critical for early detection and management to avoid the development of complications in the infected individuals and onward transmission to others. Testing for chlamydia and gonorrhoea using molecular methods is costly, prohibiting its widespread use globally. There is a possibility to reduce testing costs if pooling samples from the same individual is feasible. 

The WHO commissioned Associate Professors Jason Ong and Eric Chow from Monash University to examine the accuracy of pooled samples from multiple anatomic sites from one individual to detect chlamydia and gonorrhoea.

They conducted a systematic review and meta-analysis, which found 17 eligible studies. Most studies were conducted in high-income countries (82.6%, 14/17) and focused on men who have sex with men (70.6%, 12/17). Fourteen studies provided 15 estimates for the meta-analysis for CT with data from 5891 individuals. Compared to individual testing, they found that pooled testing had 93.1% sensitivity and 99.4% specificity for chlamydia; and 94.1% sensitivity and 99.6% specificity for gonorrhoea. Studies report significant cost savings (by two-thirds to a third).

Multisite pooled testing is a promising approach to improve testing coverage for chlamydia and gonorrhoea in resource-constrained settings with a small compromise in sensitivity but with a potential for significant cost savings.

Reference

Aboud, L., Xu, Y., Chow, E.P.F. et al. Diagnostic accuracy of pooling urine, anorectal, and oropharyngeal specimens for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae: a systematic review and meta-analysis. BMC Med 19, 285 (2021). https://doi.org/10.1186/s12916-021-02160-9