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New point of care Chlamydia Rapid Test—bridging the gap between diagnosis and treatment: performance evaluation study

BMJ 2007; 335 doi: https://doi.org/10.1136/bmj.39402.463854.AE (Published 06 December 2007) Cite this as: BMJ 2007;335:1190
  1. Lourdes Mahilum-Tapay, director of scientific affairs1,
  2. Vivian Laitila, director of regulatory affairs1,
  3. James J Wawrzyniak, research assistant2,
  4. Helen H Lee, reader in medical biotechnology2,
  5. Sarah Alexander, clinical scientist3,
  6. Catherine Ison, director3,
  7. Alison Swain, senior doctor4,
  8. Penelope Barber, chief executive officer4,
  9. Ines Ushiro-Lumb, virologist5,
  10. Beng T Goh, consultant, genitourinary medicine clinics5
  1. 1Diagnostics for the Real World (Europe) Ltd, Cambridge Science Park, Cambridge CB4 0WG
  2. 2University of Cambridge, Department of Haematology, Diagnostics Development Unit, EABC Site, Long Road, Cambridge CB2 2PT
  3. 3Sexually Transmitted Bacteria Reference Laboratory, Health Protection Agency Centre for Infections, London NW9 5HT
  4. 4Brook in Birmingham, 56-61 John Bright Street, Birmingham B1 1BL
  5. 5Barts and The London NHS Trust, London E1 1BB
  1. Correspondence to: H H Lee hl207{at}cam.ac.uk
  • Accepted 9 October 2007

Abstract

Objective To evaluate the performance of a new Chlamydia Rapid Test with vaginal swab specimens as a potential tool for chlamydia diagnosis and screening.

Design Performance evaluation study.

Settings A young people’s sexual health centre (site 1) and two genitourinary medicine clinics (sites 2 and 3) in the United Kingdom.

Participants 1349 women aged between 16 and 54 attending one of the three clinics.

Main outcome measures Sensitivity, specificity, positive predictive value, and negative predictive value of the Chlamydia Rapid Test versus polymerase chain reaction and strand displacement amplification assays; correlation between the Chlamydia Rapid Test visual signal and organism load; acceptability to participants of self collected vaginal swabs as the specimen type for Chlamydia testing.

Results Polymerase chain reaction positivity rates for Chlamydia trachomatis infection were 8.4% (56/663) at site 1, 9.4% (36/385) at site 2, and 6.0% (18/301) at site 3. Compared with polymerase chain reaction assay, the resolved sensitivity, specificity, positive predictive value, and negative predictive value of the Chlamydia Rapid Test were 83.5% (91/109), 98.9% (1224/1238), 86.7% (91/105), and 98.6% (1224/1242). Compared with strand displacement amplification assay, sensitivity and specificity of the Chlamydia Rapid Test were 81.6% (40/49) and 98.3% (578/588). Organism load of self collected vaginal swabs ranged from 5.97×102 to 1.09×109 Chlamydia plasmids per swab, which correlated well with the Chlamydia Rapid Test’s visual signal (r=0.6435, P<0.0001). Most (95.9%) surveyed participants felt comfortable about collecting their own swabs.

Conclusions The performance of the Chlamydia Rapid Test with self collected vaginal swabs indicates that it would be an effective same day diagnostic and screening tool for Chlamydia infection in women. The availability of Chlamydia Rapid Test results within 30 minutes allows for immediate treatment and contact tracing, potentially reducing the risks of persistent infection and onward transmission. It could also provide a simple and reliable alternative to nucleic acid amplification tests in chlamydia screening programmes.

Footnotes

  • We thank I Clarke (University of Southampton) for providing the plasmid pCTL12A used as a standard in the quantitative analysis; J White (Guy’s and St Thomas’ Hospital, London), J-P Allain (University of Cambridge), and ECB Nadala Jr (Diagnostics for the Real World (Europe) Ltd) for critical review of the manuscript; and the participants and staff at the three clinical sites of the study.

  • Contributors: HHL was the chief investigator of the study. LM-T, VL, and HHL prepared the clinical plan and acted as clinical monitors. LM-T wrote the first draft of the manuscript. VL and JJW were responsible for data entry and analysis. BTG, IU-L, and PB were the principal investigators at the clinical sites. AS was the clinician involved in the study at site 1. CI and SA tested and analysed discordant samples. All authors participated in drafting and revising the manuscript, and all approved the final version. HHL is the guarantor.

  • Funding: Wellcome Trust grant to the University of Cambridge.

  • Competing interests: JJW and HHL are equity holders of a spin-off company, Diagnostics for the Real World, based on the rapid test technologies developed at the University of Cambridge. Both the University of Cambridge and the Wellcome Trust are also equity holders of the company.

  • Ethical approval: Moorfields and Whittington Research Ethics Committee (05/Q0504/53); Brook in Birmingham Research Ethics Committee.

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

  • Accepted 9 October 2007
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