Minimal inhibitory effect of male urine on detection of Chlamydia trachomatis by Roche Amplicor PCR.

A total of 1120 specimens of fresh urine from male patients was tested for Chlamydia trachomatis with the Roche Amplicor PCR Kit and an in-house PCR assay. The in-house PCR had an internal control to monitor inhibitory effects of clinical specimens on the PCR assay. All urine samples were processed within 24-48 h of collection and DNA was extracted on the same day that the assays were performed. Specimens that gave discrepant PCR results were tested by a reference laboratory with both the Roche Amplicor kit and their in-house PCR assay. Of the 1120 samples, 174 gave positive results in both assays and 942 gave negative results in both assays. Only one specimen showed an inhibitory effect on the in-house PCR assays, as indicated by failure to produce the internal control PCR product. This specimen gave negative results by both assays. There were four discrepant results in the two PCR assays. One was a false negative result obtained with the Roche Amplicor kit and the remaining three discrepant results could not be resolved because there was an insufficient quantity of specimen. This study demonstrated that the Roche Amplicor kit could effectively detect C. trachomatis in urine specimens from this population of male patients with negligible inhibition of PCR.