Urine-based testing for Chlamydia trachomatis using polymerase chain reaction, leucocyte esterase and urethral and cervical smears.

The performance of Roche polymerase chain reaction (PCR) Amplicor to detect Chlamydia trachomatis in first-voided urine specimens from 422 males and 456 females attending two clinics for sexually transmitted infections was evaluated in comparison with cultures of urethral and cervical specimens. At the same time, the ability of leucocyte esterase (LE) in first-voided urine and the presence of leucocytes in urethral and cervical smears to identify C. trachomatis-infected individuals based on PCR and culture was determined. The prevalence of C. trachomatis infection was 10.9% in men and 7.7% in women. Sensitivity, specificity, positive predictive value and negative predictive value of Amplicor was 93.5%, 99.7%, 97.7% and 99.2% in males and 91.4%, 99.5%, 94.1% and 99.3% in females. All Chlamydia-infected men were identified by means of a combination of urethritis (4 leucocytes in the urethral smear) and/or a positive LE test in urine, although the specificity was only 42.2%. In women, the combination of urethritis and/or cervicitis and/or a positive LE test identified 85.7% of Chlamydia-infected patients with a specificity of 38.2%. It is concluded that a combination of urethral and/or cervical smears and LE testing of urine can be used as a screening test to select patients, especially males, for specific C. trachomatis testing.