[Evaluation of the cobas 4800 CT/NG test for detecting Chlamydia trachomatis]

To evaluate the new automated system cobas 4800 CT/NG test for detection of Chlamydia trachomatis in urogenital specimens.

We analyzed 696 specimens (488 swabs from urethral or cervical specimens, and 208 urines) to detect C. trachomatis. The results of the cobas 4800 CT/NG test (c4800) were compared to those obtained with Cobas AMPLICOR CT/NG test (CAM). Discordant results were analyzed with a conventional PCR assay and microchip electrophoresis system in agarose gel, MultiNA.

We made two simultaneous analyses. In the first one, we compared the results obtained with swab specimens using the c4800 system and CAM. In this case, the sensitivity, the specificity, the positive and negative predictive values (PPV and NPV) were: 77.9%, 100%, 100% and 96% respectively. In the second one, we compared the results obtained for urine and its corresponding swab specimens on the c4800. The values obtained were: 100%, 98.9%, 92.9% and 100% respectively. The kappa values of these comparisons were: 0.857 for swab specimens on the c4800 and CAM, and 0.957 for urine versus swab specimens on the c4800.

The results obtained with c4800 system were completely comparable with those obtained with CAM. We also noted an excellent correlation with these results when we compared swab specimens with their urine samples in the c4800 system. Therefore this sample type could be used routinely to diagnose infections in men and women.