UG3 A service evaluation comparing online-based testing to clinic-based testing for rectal chlamydia and gonorrhoea in women

Introduction

Anorectal sexually transmitted infections in women is an understudied area, with variable rates of infection reported in studies. Rectal infections are usually asymptomatic and carry the risk of onward transmission. Although women are offered rectal swabs in clinic if they report anal sex, there is variable offer of rectal swabs for women via home-based testing in the UK. SHUK is the online postal self-sampling service (OPSS) provider for our service, and we offer women rectal swabs for triple-site testing if they report anal sex.

Aim

To assess the effectiveness of offering women rectal swabs via OPSS and compare this to clinic-based testing in terms of detection rates of rectal chlamydia (CT), gonorrhoea (GC), and isolated, single-site rectal infections.

Methods

We conducted a retrospective analysis of clinic- and home-based testing data to identify women who tested positive for rectal CT/GC between April 1- December 31, 2022.

Results

The return rate of OPSS was 71.4%, with a processing rate of 98%.

Discussion

Detection rates for rectal chlamydia and gonorrhoea in women via OPSS were lower than clinic-based testing (4.1% vs 8.3%, p=0.002), likely due to higher rates of asymptomatic service users. OPSS identified low rates of isolated, single-site rectal infection (0.8% vs 2.6%; p=0.005). Based on these results, unselected triple-site testing offers minimal detection advantage in our OPSS population. Targeted testing might yield higher detection rates, but implementation may be dependent on individual service cost pressures.