[Direct diagnosis of Chlamydia trachomatis genital infections: culture or PCR?]

PCR and culturing were compared for the routine diagnosis of Chlamydia trachomatis infections. Two laboratories experienced in both techniques participated in the study, which included 513 specimens. Both techniques were performed on each specimen; the portion of the specimen used for PCR was divided in two, and each half was sent to one of the two laboratories, where the tests were run in a blinded fashion. The PCR primers used by the two laboratories matched different parts of the bacterial genome. PCR inhibitors were looked for in all specimens. Overall, PCR was more sensitive than culturing; the difference was marked for sperm and endopelvic specimens and nonsignificant for urethral and cervical specimens. False-positive PCR results were few in number; there were no consistent false-positive results when each specimen was amplified twice. PCR inhibitors were rarely present in urethral and cervical specimens but were found in 7% of sperm and endopelvic specimens. PCR inhibitors should be looked for routinely during PCR testing of sperm or endopelvic specimens.