Large-scale testing of women in Copenhagen has not reduced the prevalence of Chlamydia trachomatis infections.

OBJECTIVE: To examine the impact of a stable, large-scale enzyme immunoassay (EIA) Chlamydia trachomatis testing situation in Copenhagen, and to estimate the impact of introducing a genomic-based assay with higher sensitivity and specificity. METHODS: Over a five-year study period, 25 305-28 505 women screened for chlamydial infection each year, corresponding to 19.3% of the female population in Copenhagen, Denmark, were analyzed. RESULTS: The C. trachomatis age-specific examination percentage and age-specific positive percentage were unchanged during the study period. For EIA, the age-specific positive predictive value of a test decreased from 94% at age 17 to only 50% at age 34 years. Irrespective of the choice of diagnostic test, only about 30% of chlamydial infections would be diagnosed, given current strategies. CONCLUSION: Although genomic detection assays will increase the positive and negative predictive values of the Chlamydia test result, new screening strategies for both men and women in younger age groups will be necessary if chlamydial infections are to be curtailed.