Background/introduction BASHH standards recommend rectal chlamydia sampling in women with increased risk. However, studies show high rates of rectal chlamydia in women, with concerns over treatment failures and risk of genital re-infection

Aim(s)/objectives To determine if rectal chlamydia screening in females should be universal.

Methods As part of a selfswab versus clinician trial we asked females about frequency of vaginal, receptive anal, and oral sex, and correlated this with chlamydia NAATs from these sites.

Results Recruitment to February 2016 included 1041 women. All consented to rectal sampling; none had rectal symptoms. 53% reported no prior receptive anal sex. 204 women had chlamydia (CT) positive NAATs at one or more sites: 176 (16.9%) VVS positive (86% of all CT positives); 190 (18.3%) rectal positive (93% of total CT positives); 49 (4.7%) pharyngeal positive. Rectal swabs were significantly more likely to detect CT than VVS: OR 2.75 (95% CI 1.22–6.18) p = 0.02 McNemar test. The table shows percentage women by positive site(s) reporting no anal sex. 92/190 (48.4%) of those with one site or combination rectal CT reported no previous anal sex. Of the 168 with VVS and rectal positive NAATs, the AC2 Reactive Light Units levels were equivalent, suggesting active infection at both sites.

Discussion/conclusion In this sample of women with no rectal symptoms, the rectum was the most prevalent site for chlamydia infection, and rectal swabs found significantly more infections than VVS. There was no association with reported anal sex indicating sexual risk history is unreliable for targeted screening in women.