CLINICAL-EVALUATION OF A NEW POLYMERASE CHAIN-REACTION ASSAY FOR DETECTION OF CHLAMYDIA-TRACHOMATIS IN ENDOCERVICAL SPECIMENS

A clinical evaluation of the Amplicor polymerase chain reaction (PCR) assay for the detection of Chlamydia trachomatis in endocervical swabs (Roche Molecular Systems, Branchburg, N.J.) is described. This new cl inical system used one-step sample preparation, amplification with bio tinylated cryptic plasmid primer pairs (CP24-CP27), uracil-N-glycosyla se (AmpErase), and a microtiter format for amplicon capture and detect ion. Culture with McCoy cells in duplicate 1-dram (3.697-ml) vials wit h fluorescent immunostaining was the reference system. Endocervical sw ab samples from 945 women provided 74 culture-positive specimens, of w hich PCR detected 71. The initial PCR result was positive for 12 addit ional specimens. Arbitration of the PCR-positive, culture-negative sam ples by PCR with major outer membrane protein primers, duplicate cultu re, elementary body direct fluorescent-antibody staining, and DNA extr action PCR showed that all 12 samples were positive for chlamydia, rai sing the number of truly positive samples from 74 to 86. After arbitra tion the true sensitivities of PCR and culture were %.5 and 86%, respe ctively (P = 0.02). Specificities for both were 100%. For PCR, the pos itive and negative predictive values were 100 and 99.7%, respectively. Total test efficiency was 99.7%. A high-test-volume (121 samples) tim ing study with all items included in the College of American Pathologi sts work load method indicated that this PCR format took approximately 3 min per sample. Because of the high sensitivity, specificity, and i mproved ease of handling, we found PCR to be a good alternative to cul ture for detection of C. trachomatis.