PERFORMANCE-CHARACTERISTICS OF THE GEN-PROBE PROBE COMPETITION ASSAY USED AS A SUPPLEMENTARY TEST FOR THE GEN-PROBE PACE-2 AND PACE-2C ASSAYS FOR DETECTION OF CHLAMYDIA-TRACHOMATIS

The performance characteristics of the Gen-Probe Probe Competition Ass ay (PCA) used in conjunction with the Gen-Probe PACE 2 and 2C direct d etection assays for Chlamydia trachomatis were examined, Data collecte d by five public health laboratories by using the Gen-Probe PACE 2 wer e pooled and analyzed, Of 25,081 endocervical and male urethral specim ens tested by the PACE 2 assay, 773 were tested by PCA. Of 334 specime ns initially positive by the PACE 2 assay with an initial PACE 2 resul t of greater than 2,000 relative light units (RLU), 333 (99.7%) were p ositive by PCA while 242 of 339 (71.4%) specimens with an initial resu lt between the cutoff and 2,000 RLU were positive by PCA, and 35 of 10 0 (35%) specimens with initial results between 200 RLU and the cutoff were positive by PCA, An additional 10,938 specimens were tested by th e PACE 2C assay, Of these, positive PCA results were obtained for 187 of 188 (99.5%) specimens with initial results of greater than 2,000 RL U, 99 of 163 (60.7%) of specimens in the range of cutoff to 2,000 RLU, and 12 of 100 (12%) in the range of 200 RLU to the cutoff, These resu lts indicate that specimens greater than 2,000 RLU do not require a su pplemental test and that additional positive results can be obtained b y testing specimens with an initial result below the cutoff.