Use of the APTIMA Combo 2 Assay and a Secondary Algorithm to Detect and Confirm Chlamydia trachomatis in Rectal-Only Infections

We sought to confirm the results of 81 rectal specimens positive for Chlamydia trachomatis by the APTIMA Combo 2 assay among patients with concurrently collected negative genitourinary specimens. A total of 79 (97.5%) samples were confirmed by the APTIMA single target assay and/or sequencing of the C. trachomatis ompA gene.