Low prevalence of Chlamydia trachomatis by urinary ligase chain reaction in women patients in the emergency department.

Unlabelled: Recent studies suggest that women with acute urethral syndrome or abdominal pain, presenting to emergency departments (EDs), have a high prevalence of Chlamydia trachomatis.

Objectives: To estimate the prevalence of C. trachomatis in women presenting to an ED and to see whether those with dysuria or abdominal pain have a higher prevalence of C. trachomatis.

Methods: The authors conducted a prospective cross-sectional study of C. trachomatis in the urine of women aged 18 to 50 years who had a urinalysis performed at a university/county ED from February through May 1998. Urine specimens were labeled for the presence of symptoms and analyzed for C. trachomatis by ligase chain reaction (LCR). Polymerase chain reaction (PCR) testing of cervical swabs for C. trachomatis was done for usual clinical indications. Difference in proportions of positive LCR tests among patients was tested with Fisher's exact test. Agreement between PCR and LCR was measured using Cohen's kappa statistic.

Results: Of 397 women whose urine was tested, 280 had symptoms of dysuria, abdominal pain, or both, and 117 had no symptoms. The overall prevalence of C. trachomatis by LCR was 3.8% (95% CI = 2.1% to 6.2%); and the combined PCR-LCR prevalence was 4.3% (95% CI = 2.5% to 6.8%). The presence of symptoms was not associated with a positive LCR test for C. trachomatis (p = 0.26, power = 0.8, alpha = 0.05, difference 3% vs. 12%). In the 172 patients who had both a PCR cervical swab and urine LCR, agreement was excellent (kappa = 0.67, 95% CI = 0.45 to 0.90).

Conclusions: This ED had a surprisingly low prevalence of C. trachomatis. Women with symptoms were not more likely to test positive than those without.