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Field evaluation of two point-of-care tests for syphilis among men who have sex with men, Verona, Italy
  1. Antonella Zorzi1,
  2. Maddalena Cordioli2,
  3. Lorenzo Gios3,
  4. Paola Del Bravo4,
  5. Igor Toskin5,
  6. Rosanna W Peeling6,
  7. Karel Blondeel5,7,
  8. Giuseppe Cornaglia1,
  9. James Kiarie5,
  10. Ronald Ballard5,
  11. Massimo Mirandola2,3
  1. 1 Virology and Microbiology Unit, Department of Pathology and Diagnostics, Verona University Hospital, Verona, Italy
  2. 2 Infectious Diseases Section, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
  3. 3 Regional Coordination Centre for European Project Management, Verona University Hospital, Verona, Italy
  4. 4 Infectious Diseases and Tropical Medicine Unit, Department of General Medicine, Verona University Hospital, Verona, Italy
  5. 5 Department of Reproductive Health and Research, World Health Organization, Geneva, Switzerland
  6. 6 International Diagnostics Centre, Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK
  7. 7 Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
  1. Correspondence to Maddalena Cordioli, Infectious Diseases and Tropical Medicine Unit, Verona University Hospital Piazzale L.A. Scuro 10, Verona 37134, Italy; maddalena.cordioli{at}univr.it

Abstract

Objectives The incidence of HIV and syphilis among men who have sex with men (MSM) in Europe has recently increased. Rapid point-of-care tests (POCTs) for syphilis can improve access to screening. The purpose of this study was to evaluate the performance of two syphilis POCTs compared with laboratory tests among MSM.

Methods The study was undertaken in Verona, Italy. Asymptomatic MSM, potentially exposed to syphilis, were enrolled prospectively. The POCTs evaluated were SD Bioline Syphilis 3.0 and Chembio DPP Syphilis Screen & Confirm Assay on both serum and fingerprick blood. The results of the POCTs were read by the naked eye by two independent readers and their concordance assessed.

Results A total of 289 MSM were enrolled in the study. Based on laboratory tests, 35 MSM (12.1%) were TPPA-positive alone and 16 (5.5%) were both Treponema pallidum particle agglutination test (TPPA) and rapid plasma reagin (RPR)-positive. The specificities of both POCTs were above 99% on both serum and fingerstick blood specimens, while sensitivities varied considerably. The sensitivity of the SD Bioline test was lower on fingerprick blood (51.4% and 54.3%, readers 1 and 2, respectively) compared with that on serum (80.0% and 82.9%). In contrast, the Chembio test exhibited similar sensitivity values for serum and fingerprick samples (57.7% and 64.0% on serum vs 65.4% and 69.2% on fingerprick for the treponemal component; 63.6% on both samples by both readers for the non-treponemal component). The positive predictive value ranged between 100% and 93.9% for the treponemal component of both syphilis POCTs, but was lower (76.3%–100%)%) for the non-treponemal component of the Chembio POCT. The negative predictive value surpassed 90% for both tests on both samples. The agreement between readers was very high (>99%).

Conclusion The diagnostic performance of the syphilis POCTs was lower than expected; however, considering the prevalence of syphilis among MSM, POCTs should be recommended to improve syphilis detection among MSM.

  • syphilis
  • men who have sex with men
  • screening
  • point-of-care testing
  • evaluation study

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Footnotes

  • Handling editor Jackie A Cassell

  • Contributors MM, LG, AZ, MC, IT and RWP participated in the design of the survey and the organisation and implementation of the survey in the survey cities. This analysis was conceived by MM, IT and RWP. Data were analysed by MM, LG and MC. The first manuscript draft was jointly written by MC, LG, MM and AZ. MC, LG, MM, KB, PDB, AZ, IT, RWP, JK, GC, RB contributed writing to the following drafts. All authors read and approved the final manuscript.

  • Funding This manuscript is partially based on data collected in the context of the Sialon II project, co-funded under the Second Programme of Community action in the field of health (2008–2013) (Work Plan 2010).

  • Disclaimer The author(s) is(are) staff member(s) of the World Health Organization. The author(s) alone is(are) responsible for the views expressed in this publication and they do not necessarily represent the views, decisions or policies of the World Health Organization.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval WHO Research Project Review Panel (protocol number A65), WHO Research Ethics Review Committee (protocol number RPC557) and Local Ethic Committee - Comitato Etico per la Sperimentazione Clinica delle province di Verona e Rovigo (protocol numbers 272CESC, CE2341, CE2408).

  • Provenance and peer review Commissioned; externally peer reviewed.

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