Objectives: To develop and validate selective screening criteria for asymptomatic Chlamydia trachomatis infections in the general population.
Methods: 11,505 people, aged 15-40 years, registered in 16 general practices in Amsterdam were invited to return by mail a home obtained first void urine sample and a questionnaire. Participants were randomly allocated into a development group (75%) or a validation group (25%). C trachomatis infection was determined by the ligase chain reaction. In the development group a set of criteria was identified by means of stepwise logistic regression analysis. The diagnostic accuracy (area under the ROC curve; AUC) and sensitivity, and the corresponding percentage of people selected for screening were calculated. The criteria developed in this study were applied to the validation group.
Results: The prevalence of asymptomatic C trachomatis infections among men was found to be 2.4% (1.7-3.0), and among women 2.8% (2.2-3.4). Screening men, based on Surinam/Antillean origin and painful micturition, yielded an AUC of 0.58 (0.55-0.60). Screening women, based on Surinam/Antillean origin, new sex partner in the previous 2 months, and unmarried/not cohabiting, yielded an AUC of 0.67 (0.65-0.69). Application of the criteria for men to the validation group yielded an AUC of 0.53 (0.48-0.57); by screening 10% of the men, 15% of the cases were detected. The AUC of the criteria for women in the validation group was 0.58 (0.54-0.61); by screening 51% of the women, 63% of the cases were detected.
Conclusion: The prevalence of asymptomatic C trachomatis infections in Amsterdam is less than 3%. No suitable selective screening criteria for the general population could be identified.