Diagnosis of Chlamydia trachomatis infections in a sexually transmitted disease clinic: evaluation of a urine sample tested by enzyme immunoassay and polymerase chain reaction in comparison with a cervical and/or a urethral swab tested by culture and polymerase chain reaction.

OBJECTIVE: To evaluate the value of a urine sample for diagnosing Chlamydia trachomatis infection in an STD clinic in a prospective study of samples collected from 410 consecutive STD patients (167 female and 243 male).
METHODS: Urine samples were tested by enzyme immunoassay (EIA) and polymerase chain reaction (PCR) in comparison with cervical and/or urethral swabs tested by PCR and cell culture. A questionnaire was completed for a total of 320 patients concerning symptoms, and determining whether they were controls, contacts or were being tested subsequent to legal abortion.
RESULTS: The overall prevalence of C. trachomatis infection was 11.5%. At least 40% of patients were asymptomatic. Of the C. trachomatis-positive patients, 85% were diagnosed by testing urine, compared to 91% by testing swabs. For urine tests, the sensitivities of PCR were 66.7% and 71.9% for female and male patients, respectively, and the sensitivities of EIA were 40.0% and 62.5%, or 46.7% and 71.9%, for female and male patients, respectively, by including a 30% gray zone below the cut-off value. For swabs, the sensitivities of PCR were 93.3% and 87.5% for female and male patients, respectively, and equal to the sensitivities of culture. In total, 3.3% of controls and 35% of contacts were found to be C. trachomatis positive.
CONCLUSION: The use of urine samples for the diagnosis of C. trachomatis infections was effective, but urine samples should be additional to conventional swab(s) instead of replacing. Partner notification and a confirmation of cure is recommended.