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Evaluation of the cobas 4800 CT/NG test for detecting Chlamydia trachomatis and Neisseria gonorrhoeae
  1. Rebecca Rockett1,2,
  2. Namraj Goire1,2,
  3. Athena Limnios3,
  4. Mark Turra4,
  5. Geoffrey Higgens4,
  6. Stephen B Lambert1,2,
  7. Cheryl Bletchly5,
  8. Michael D Nissen1,2,5,
  9. Theo P Sloots1,2,5,
  10. David M Whiley1,2
  1. 1Queensland Paediatric Infectious Diseases Laboratory, Sir Albert Sakzewski Virus Research Centre, Queensland Children's Medical Research Institute, Children's Health Service District, Queensland, Australia
  2. 2Clinical Medical Virology Centre, University of Queensland, Queensland, Australia
  3. 3WHO Collaborating Centre for STD and HIV, Microbiology Department, South Eastern Area Laboratory Services, Prince of Wales Hospital, Sydney, New South Wales, Australia
  4. 4Infectious Diseases Laboratories, Institute of Medical & Veterinary Science, Adelaide, South Australia, Australia
  5. 5Microbiology Division, Pathology Queensland Central, Royal Brisbane and Women's Hospital Campus, Queensland, Australia
  1. Correspondence to Dr David M Whiley, Queensland Paediatric Infectious Diseases Laboratory, Clinical Virology Research Unit, SASVRC, Royal, Children's Hospital, Hertson Road, Herston, Brisbane 4029, Australia; d.whiley{at}


Objectives To investigate the performance of the fully automated cobas 4800 CT/NG test for detection of Chlamydia trachomatis and Neisseria gonorrhoeae.

Methods The study was conducted using 900 clinical specimens (496 urine and 404 swab specimens) for C trachomatis testing, of which 498 specimens (318 urine and 180 swab specimens) were also tested for N gonorrhoeae. The results of the cobas 4800 CT/NG test were compared with those obtained from the Roche COBAS AMPLICOR CT/NG and COBAS TaqMan CT assays. N gonorrhoeae-positive specimens were further tested using in-house, real-time PCR assays. A panel of 223 Neisseria isolates was used to further investigate the performance of the cobas 4800 N gonorrhoeae assay.

Results For urine specimens, the sensitivity, specificity and negative and positive predictive values of the cobas 4800 CT/NG test were 94.5%, 99.5%, 98.8% and 97.7%, respectively, for C trachomatis, and 92.9%, 100%, 99.7% and 100%, respectively, for N gonorrhoeae. For swab specimens, the sensitivity, specificity and negative and positive predictive values were 92.0%, 100%, 99.5% and 100%, respectively, for C trachomatis, and 100%, 99.4%, 100% and 90.0%, respectively, for N gonorrhoeae. All N gonorrhoeae isolates were positive and all non-gonococcal Neisseria strains were negative by the cobas 4800 N gonorrhoeae assay.

Conclusions The cobas 4800 CT/NG test is suitable for high through-put identification of C trachomatis and N gonorrhoeae infections.

  • Chlamydia trachomatis
  • DNA amplification
  • Neisseria gonorrhoea

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  • Funding Financial support was provided by Roche Diagnostics, Australia, for specimen transport and cobas 4800 CT/NG testing costs.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.