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External quality assurance with dried tube specimens (DTS) for point-of-care syphilis and HIV tests: experience in an indigenous populations screening programme in the Brazilian Amazon
  1. Adele Schwartz Benzaken1,2,
  2. Maria Luiza Bazzo3,
  3. Enrique Galban1,
  4. Ione Conceição Pereira Pinto1,
  5. Christiane Lourenço Nogueira3,
  6. Lisléia Golfetto3,
  7. Nina Schwartz Benzaken4,
  8. Kimberly A Sollis5,
  9. David Mabey5,
  10. Rosanna W Peeling5
  1. 1STI/AIDS Department at Alfredo da Matta Foundation, Manaus, Brazil
  2. 2UNAIDS, Brasilia, Brazil
  3. 3Department of Clinical Analysis, Federal University of Santa Catarina, Florianópolis, Brazil
  4. 4Medical School of Nilton Lins University, Manaus, Brazil
  5. 5Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK
  1. Correspondence to Kimberly A Sollis, Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; Kimberly.Sollis{at}lshtm.ac.uk

Abstract

Objectives The availability of point-of-care (POC) tests for infectious diseases has revolutionised the provision of healthcare for remote rural populations without access to laboratories. However, quality assurance for POC tests has been largely overlooked. We have evaluated the use and stability of dry tube specimens (DTS) for External Quality Assurance (EQA) for HIV and syphilis screening in remote indigenous populations in the Amazon region of Brazil.

Methods All healthcare workers (HCWs) participating in the community-screening were trained. We used HIV and syphilis DTS panels developed by the reference laboratory, containing samples with negative and positive results at different antibody concentrations, for both infections. DTS panels were distributed to HCWs in the communities for reconstitution and testing using POC HIV and syphilis tests. The results of testing were sent to the reference laboratory for marking and remedial action taken where necessary.

Results In total 268 HCWs tested 1607 samples for syphilis and 1608 samples for HIV. Results from HCWs showed a concordance rate of 90% for syphilis and 93% for HIV (κ coefficients of 0.74 and 0.78, respectively) with reference laboratories. Most false negatives were in samples of very low antibody concentration. DTS syphilis specimens produced the expected results after storage at 2–8°C or at 18–24°C for up to 3 weeks.

Conclusions The results show that POC tests for syphilis and HIV give valid results in environments where traditional tests do not work, but errors in the interpretation of POC test results were identified by the EQA programme using DTS. EQA using DTS can help to improve the quality of screening programmes using POC tests in remote regions.

  • TESTING
  • SYPHILIS
  • HIV
  • SCREENING

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