title: Performance of the GeneXpert CT/NG assay compared to that of the Aptima AC2 assay for detection of rectal Chlamydia trachomatis and Neisseria gonorrhoeae by use of residual Aptima Samples.
abstract: There are currently no commercially available molecular assays for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in rectal swabs with regulatory approval. We compared the Cepheid GeneXpert CT/NG assay with the GenProbe Aptima Combo2 assay, using 409 rectal swabs. Using Aptima as the gold standard, the sensitivity, specificity, and positive and negative predictive values of GeneXpert for the detection of C. trachomatis and N. gonorrhoeae were 86%, 99.2%, 92.5%, and 98.4% and 91.1%, 100%, 100%, and 98.6%, respectively. Despite significant dilution of samples prior to GeneXpert testing, the assay performed well with excellent specificity.
authors.affiliation: Centre for Clinical Infection and Diagnostics Research, Guy's & St. Thomas' NHS Foundation Trust and King's College, London, United Kingdom. Simon.goldenberg@gstt.nhs.uk
authors.forename: S D
authors.initials: SD
authors.lastname: Goldenberg
authors.forename: J
authors.initials: J
authors.lastname: Finn
authors.forename: E
authors.initials: E
authors.lastname: Sedudzi
authors.forename: J A
authors.initials: JA
authors.lastname: White
authors.forename: C Y W
authors.initials: CY
authors.lastname: Tong
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D002690:Chlamydia Infections / Q000175:diagnosis*; D002692:Chlamydia trachomatis / Q000302:isolation & purification*; D006069:Gonorrhea / Q000175:diagnosis*; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009344:Neisseria gonorrhoeae / Q000302:isolation & purification*; D011237:Predictive Value of Tests; D012002:Rectal Diseases / Q000382:microbiology*; D012680:Sensitivity and Specificity