Performance evaluation of a new rapid urine test for chlamydia in men: prospective cohort studyBMJ 2009; 339 doi: https://doi.org/10.1136/bmj.b2655 (Published 29 July 2009) Cite this as: BMJ 2009;339:b2655
- Elpidio-Cesar Nadala, director of process development1,
- Beng T Goh, consultant in genitourinary medicine2,
- Jose-Paolo Magbanua, senior research associate3,
- Penelope Barber, chief executive officer4,
- Alison Swain, senior doctor4,
- Sarah Alexander, clinical scientist5,
- Vivian Laitila, director of regulatory affairs1,
- Claude-Edouard Michel, research associate3,
- Lourdes Mahilum-Tapay, director of scientific affairs1,
- Ines Ushiro-Lumb, consultant virologist2,
- Catherine Ison, director5,
- Helen H Lee, reader in medical biotechnology3
- 1Diagnostics for the Real World (Europe), Cambridge Science Park, Cambridge CB4 0WG
- 2Departments of Genitourinary Medicine and Virology, Barts and The London NHS Trust, London E1 1BB
- 3University of Cambridge, Department of Haematology, Diagnostics Development Unit, NHS Blood and Transplant Site, Cambridge CB2 2PT
- 4Brook in Birmingham, Birmingham B1 1BL
- 5Sexually Transmitted Bacteria Reference Laboratory, Health Protection Agency Centre for Infections, London NW9 5HT
- Correspondence to: H H Lee
- Accepted 17 February 2009
Objective To evaluate the performance of a rapid test for chlamydia with first void male urine samples as a potential tool for diagnosis and screening of chlamydial infection in men.
Design Evaluation of test performance in prospective cohort study.
Settings A young people’s sexual health centre (site 1) and a genitourinary medicine clinic (site 2) in the United Kingdom.
Participants 1211 men aged 16-73 attending either of the two sites.
Main outcome measures Sensitivity, specificity, positive predictive value, and negative predictive value of the Chlamydia Rapid Test versus polymerase chain reaction assay. Relation between the visual signal of the Chlamydia Rapid Test and organism load.
Results Detection rates for Chlamydia trachomatis infection with polymerase chain reaction were 4.4% (20/454) at site 1 and 11.9% (90/757) at site 2. Compared with polymerase chain reaction assay, the resolved sensitivity, specificity, positive predictive value, and negative predictive value of the Chlamydia Rapid Test was 82.6% (90/109), 98.5% (1085/1102), 84.1% (90/107), and 98.3% (1085/1104), respectively. The organism load in first void urine samples that were positive for chlamydia ranged from 7.28×102 to 6.93×106 plasmids/ml and correlated significantly with the visual signal of the Chlamydia Rapid Test (r=0.7897, P<0.001).
Conclusions The performance of the new Chlamydia Rapid Test with first void male urine samples indicates that it would be an effective diagnostic tool for chlamydial infection in men. The availability of test results within an hour allows for immediate treatment and contact tracing, potentially reducing the risks of persistent infection and onward transmission. The test could also provide a simple and reliable alternative to nucleic acid amplification assays for testing of male urine in chlamydial screening programmes in high prevalence settings.
We thank I Clarke (University of Southampton) for providing the plasmid pCTL12A used as a standard in the quantitative analysis; S Padmore and H Nuamah for performing on-site chlamydia testing at Brook in Birmingham; V Shah, K Gujadhur, and G Wall for performing on-site chlamydia testing at Ambrose King Centre; J Wawrzyniak (University of Cambridge) for data entry and analysis; J-P Allain (University of Cambridge) and J White (Guy’s and St Thomas’ Hospital, London) for critical review of the manuscript; and the participants and clinic staff at the two study sites.
Contributors: HHL was the chief investigator and is the guarantor. E-CN wrote the first draft of the manuscript and led in the manufacture of the Chlamydia Rapid Test kits used in the study. BTG, IU-L, and PB were the principal investigators at the clinical sites. J-PM, LM-T, VL, and HHL developed the clinical plan and acted as clinical monitors. E-CN and C-EM developed the Chlamydia Rapid Test for men. J-PM and E-CN were responsible for data entry and analysis. AS was the clinician involved in the study at site 1. SA and CI tested and analysed discordant samples. All authors participated in drafting and revising the manuscript, and all approved the final version.
Funding: The study was funded by a Wellcome Trust grant to the University of Cambridge and additional support from the NIHR Cambridge Biomedical Research Centre. The funding sources had no role in study design; in the collection, analysis, or interpretation of data; in the writing of the report; or in the decision to submit the article for publication.
Competing interests: J-PM, C-EM, and HHL are equity holders in Diagnostics for the Real World, which markets 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: The study was approved by Moorfields and Whittington research ethics committee (05/Q0504/53) and Brook in Birmingham research ethics committee and informed consent was given by all patients.
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