Which sexually active female students get themselves tested for Chlamydia trachomatis? A cohort study

Using data from the Prevention of Pelvic Infection (POPI) chlamydia screening trial, we compared the characteristics of female students who did or did not get tested for chlamydia outside the trial during 12 months' follow-up. Of the 2529 women in the trial, we excluded 68 chlamydia positives in the intervention group who were referred for treatment at baseline. Of the remaining 2461 women, 1980 (80%) answered the question about testing during follow-up on their 12 months' questionnaire and were included in the cohort. Of 1980 respondents, 529 (27%) reported having an independent chlamydia test, including 30 (48%) of 63 women with undiagnosed chlamydia at baseline. Predictors of testing included having undiagnosed chlamydia at baseline (adjusted odds ratio 2.44; 95% confidence interval 1.39-4.28), ≥2 sexual partners in the year prior to baseline (OR 1.99; 95% CI 1.60-2.48), history of sexually transmitted infection (1.63: 1.20-2.22); symptoms of pelvic discomfort, dyspareunia, abnormal vaginal discharge or inter-menstrual bleeding (1.38; 1.09-1.73); and black ethnicity (1.37, 1.06-1.76). Although more women with risk factors got tested, half of women with undiagnosed chlamydia did not get tested. To optimise detection of chlamydia, testing should be offered routinely.