Single-Sample Confirmation of Positive Gonorrhea and Chlamydia Results Using the Roche Cobas CT/NG and Cepheid Xpert CT/NG Assays.

Background: Testing for sexually transmitted infections (STIs) in preadolescent patients carries significant medical and legal implications. Guidelines from the Centers for Disease Control and Prevention (CDC) support the use of nucleic acid amplification testing (NAAT) for diagnosis of Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) in children. These guidelines also recommend confirmation of positive results by repeat testing of either the original specimen or a separately collected specimen to reduce the risk of false positives. Currently, no FDA-cleared NAATs have a specific indication for use in samples from prepubertal children or for the evaluation of suspected sexual assault. Further, if confirmation using a second assay is desired, manufacturer-specific collection kits may preclude this, necessitating a second specimen collection, which may not be feasible.

Methods: Here, we evaluate the compatibility between the Cepheid Xpert CT/NG assay and the Roche cobas CT/NG assay on samples collected in cobas PCR media.

Results: Our data suggest that the Xpert CT/NG assay is compatible with specimens collected in cobas collection medium.

Conclusions: As such, laboratories may validate this work flow as a confirmatory test on specimens collected in cobas collection medium.