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Original research
Test of cure study: a feasibility study to estimate the time to test of cure (TOC) for Neisseria gonorrhoeae and Chlamydia trachomatis infections
  1. Binta Sultan1,
  2. Paul Benn2,3,
  3. Gabriel Schembri4,
  4. Hemanti Patel5,
  5. Nataliya Brima6,
  6. Sarah Alexander7,
  7. Catherine A Ison7
  1. 1 Centre for Clinical Research in Infection and Sexual Health, Institute for Global Health, University College London, London, UK
  2. 2 The Mortimer Market Centre, Central and North West London NHS Foundation Trust, London, UK
  3. 3 Department of Clinical Development, ViiV Healthcare, Brentford, London, UK
  4. 4 Manchester Centre for Sexual Health, Manchester Royal Infirmary, Manchester, UK
  5. 5 Sexually Transmitted Bacteria Reference Unit, Public Health England Colindale, London, UK
  6. 6 King's Global Health Partnership, King's College London, London, UK
  7. 7 Sexually Transmitted Bacteria Reference Unit, Public Health England, London, UK
  1. Correspondence to Dr Binta Sultan, Centre for Research in Infection and Sexual Health, Institute for Global Health, University College London, London WC1E 6JB, UK; b.sultan{at}


Objectives Test of cure (TOC) for Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) infection is an important tool in the public health management of STIs. However, there are limited data about the optimal time to perform TOC using nucleic acid amplification tests (NAATs) for NG and CT infections. A study was performed to assess the feasibility of a larger study to determine the optimal time to TOC using NAATS.

Methods The Sexually Transmitted Bacteria Reference Unit at Public Health England undertook testing of gonococcal and chlamydial nucleic acids within neat urine stored in different conditions over 25 days to provide evidence of the stability of the nucleic acid prior to recruitment. Individuals diagnosed with uncomplicated NG or CT infection were recruited from three sexual health clinics. Individuals were asked to return nine self-taken samples from the site of infection over a course of 35 days. Survival analyses of time to first negative NAAT result for NG and CT infection and univariate regression analysis of factors that affect time to clearance were undertaken.

Results At room temperature, chlamydial DNA in urine is stable for up to 3 weeks and gonococcal DNA for up to 11 days. We analysed data for 147 infections (81 NG and 66 CT). The median time to clearance of infection was 4 days (IQR 2–10 days) for NG infection and 10 days (IQR 7–14 days) for CT infection. Vaginal CT infections took longer to clear (p=0.031). NG infection in men who have sex with men took longer to clear (p=0.052).

Conclusion Chlamydial and gonococcal nucleic acids are stable in urine before addition of preservatives, longer than recommended by the manufacturer. The TOC results suggest that it may be possible to undertake TOC for NG and CT infections earlier than current guidelines suggest and that anatomical site of infection may affect time to clearance of infection.

  • Chlamydia trachomatis
  • Neisseria gonorrhoeae
  • testing
  • guideline development
  • diagnosis

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  • Handling editor Henry John Christiaan de Vries

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  • Contributors PB and GS conceived the idea for the study and developed the study design. CAI and HP designed the urine stability testing study. HP and SA undertook analysis of the urine stability data. CAI and HP undertook the laboratory analysis of specimens for the test of cure study. BS was involved in design of the protocol, ethics submission, study recruitment and writing the manuscript. NB undertook the statistical analysis. BS, CAI, PB, GS, HP and SA reviewed and edited the manuscript.

  • Funding This study was funded by Sexually Transmitted Infection Research Foundation and British Association for Sexual Health and HIV (

  • Competing interests BS is funded through a National Institute for Health Research (NIHR) Doctoral Research Fellowship. NIHR did not have any involvement in the study or manuscript.

  • Patient consent for publication Not required.

  • Ethics approval The Hampstead Research Ethics Committee (REC no. 12LO0889) approved the study, and all patients provided written informed consent.

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

  • Data availability statement Data are available on reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information. Laboratory data available from Study dataset with deidentified participant data and protocol available from