Low diagnostic accuracy of selective screening criteria for asymptomatic Chlamydia trachomatis infections in the general population.

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.