Chlamydia trachomatis in cervical and vaginal swabs and urine specimens from women undergoing termination of pregnancy.

The study was devised to assess the prevalence of Chlamydia trachomatis in endocervical and vaginal swabs and first pass urine specimens from women presenting for termination of pregnancy (TOP) and to evaluate the performance of the tests used, namely the ligase chain reaction (LCR) and the direct fluorescence antibody (DFA) test. Eight hundred and sixty three (91%) of 948 women invited to participate agreed to do so; a complete set of results for all test-site combinations was achieved for 793 (92%). The overall prevalence of C. trachomatis was 8.54% (95% confidence interval [CI]: 7.6-10.5%) with a significant negative association with age. The sensitivity (95% CI) of the LCR test for cervical, vaginal and urine specimens was 97% (93-99%); 94% (88-99%) and 83% (75-92%), respectively. The sensitivity (95% CI) of the DFA test for cervical, vaginal and urine specimens was 93% (87-99%); 92% (86-99%) and 78% (68-88%), respectively. Concordance between the LCR and DFA test results was very high for specimens from the same site. The results indicate that nucleic acid amplification tests are appropriate for screening women seeking TOP and, indeed, other women in early pregnancy. The sensitivity of the LCR test for urine specimens was less, but the high levels of concordance observed between the LCR and DFA test results for urine specimens indicates that this was due to a lower organism load rather than inhibition of the LCR.