COMPARATIVE-EVALUATION OF DETECTION ASSAYS FOR CHLAMYDIA-TRACHOMATIS

The performances of a commercial nucleic acid hybridization test (Gen- Probe Pace 2 Chlamydia trachomatis) and two commercial enzyme immunoas says (EIAs) (Abbott Chlamydiazyme and Pharmacia Chlamydia EIA) were ev aluated against cell culture for the detection of C. trachomatis infec tion, with cervical swabs obtained from 1,037 women visiting a public sexual health center. The positivity rate by cell culture was 4.7%. Se nsitivity and specificity for each test were as follows: Gen-Probe, 95 .8 and 98.3%; Chlamydiazyme, 80.4 and 99.3%; Pharmacia EIA, 80.8 and 9 9.1%. Analysis of discrepant results with probe confirmation assay (Ge n-Probe) and direct immunofluorescence (Syva Microtrak) revealed 12 ca ses of C. trachomatis infection for which culture was negative, result ing in the definition of a true-positive case as opposed to a culture positive. The positivity rate by true-positive definition was 5.9%, an d sensitivity and specificity for each test were as follows: Gen-Probe , 96.7 and 99.6%; Chlamydiazyme, 77.5 and 100%; Pharmacia EIA, 77.0 an d 100%; cell culture, 80.0 and 100%. We conclude that the Gen-Probe Pa ce 2 C. trachomatis test is a sensitive and specific alternative to ce ll culture for the detection of C. trachomatis.