USE OF CELL-CULTURE AND A RAPID DIAGNOSTIC ASSAY FOR CHLAMYDIA-TRACHOMATIS SCREENING

Objective.-To compare a rapid, office-based test with standard cell cu lture for screening of women for Chlamydia trachomatis infections. Des ign and Settings.-An 8-month prospective crossover trial used alternat ing screening protocols in two Baltimore (Md) sexually transmitted dis ease clinics from January 2 through August 14, 1991. Participants.-Con secutive women attending the two clinics who had no indication for adm inistration of antichlamydial antibiotic therapy (eg, history of recen t sexual contact with a partner with a sexually transmitted disease, m ucopurulent cervicitis, pelvic inflammatory disease, known gonorrhea, or previously diagnosed Chlamydia infections). Interventions.-Chlamydi a screening was offered according to one of two protocols. Use of the two screening protocols was alternated between clinics each month. In the ''rapid test clinic,'' eligible women were screened with both a 30 -minute enzyme immunoassay test and tissue culture. Patients screened with the rapid test were asked to remain in the clinic until their rap id assay results were available so that, if positive, the patients cou ld be treated. In the ''routine screening clinic,'' eligible women wer e screened for Chlamydia by cell culture. Women identified as being in fected with Chlamydia by screening culture were later confidentially n otified of their test results by health department disease interventio n specialists and referred for therapy. Main Outcome Measures.-Perform ance of screening tests for bringing infected patients to therapy; tim e intervals between initial clinic visits and therapy; and pelvic infl ammatory disease occurring between initial visits and therapy. Results .-Chlamydia cultures were positive in 100 (6.6%) of 1526 women screene d with the solid-phase immunoassay, 47 of which were detected and trea ted on the basis of rapid test results. In contrast, 93 (74%) of 126 w omen with positive screening cultures returned to the clinic and recei ved therapy. The median interval between testing and therapy for women with positive screening cultures was 14 days, and three (3.2%) develo ped pelvic inflammatory disease in the interval between testing and re turn for therapy. Conclusions.-Neither cell culture nor a rapid diagno stic test performed well for ensuring therapy of women with Chlamydia infections. The sensitivity of the rapid diagnostic test was low, and nearly one fourth of the women with positive screening cultures did no t return for therapy. Evaluation of screening for Chlamydia should con sider the utility of strategies for bringing patients to treatment, as well as the more usual measures of test performance, such as sensitiv ity, specificity, and predictive values.