DIAGNOSIS OF CHLAMYDIA-TRACHOMATIS ENDOCERVICAL INFECTIONS BY A COMMERCIAL POLYMERASE CHAIN-REACTION ASSAY

We evaluated a prototype polymerase chain reaction (PCR)-based assay f or Chlamydia trachomatis developed by Roche Molecular Systems to detec t endocervical infection in women. Of 587 endocervical samples obtaine d from women attending the Harborview Medical Center sexually transmit ted diseases clinic, 58 (10%) were positive for C. trachomatis by cell culture. Compared with culture, the PCR method had a sensitivity of 8 8% (51 of 58) and a specificity of 99.2% (525 of 529). The positive an d negative predictive values were 92.7% (51 of 55) and 98.7% (525 of 5 32), respectively. After resolution of discrepant results whereby true positives were considered to be either culture-positive patients (58 patients) or culture-negative patients positive upon PCR analysis usin g both plasmid- and major outer membrane protein-based primers (4 pati ents), the resolved sensitivities of the PCR and culture were 89 and 9 3%, respectively. We subsequently performed a second analysis of 362 w omen, comparing the proposed commercial PCR assay from Roche Molecular Systems with chlamydia cultures. Thirty (8%) women were infected with C. trachomatis. Compared with culture, the assay had a sensitivity of 60% (18 of 30) and a specificity of 99% (328 of 332). Repeat PCR assa y done 2 to 5 days later subsequently yielded positive results for 7 o f 11 PCR-negative samples from culture-positive women. We conclude tha t the Roche Molecular Systems PCR assay provides highly specific resul ts compared with culture in a high-risk population of women. Further s tudy is needed, however, to more clearly define the sensitivity of the PCR assay in detecting endocervical C. trachomatis infection in women and to identify factors that may compromise sensitivity.