Background The availability of point of care(POC) tests for infectious diseases has revolutionised the provision of health care for remote rural populations without access to laboratories. However, little attention has been given to quality assurance for POC tests. In a screening project that tested 45,226 adults of both sexes by 268 Health Care Workers(HCWs), in remote indigenous populations in the Amazon region of Brazil, where the overall prevalence of syphilis was 1.6%, and of HIV 0.1%, we evaluated the use of Dry Tube Specimens(DTS) for External Quality Assurance(EQA) for POC HIV and Syphilis tests.
Methods The EQA programme was implemented from March 2010 to March 2011 using DTS panels developed by a reference laboratory, containing samples with negative and positive results at different antibody concentrations, for HIV and Syphilis infection. These were re-suspended and tested in the communities by each HCW. We also conducted stability tests for the panels at the reference laboratory.
Results Results from 268 HCWs, responsible for implementing the POC tests at six Indigenous District(DSEI) participated in the EQA programme, showed a concordance rate of 90% for syphilis and 93% for HIV (Kappa coefficients of 0.74 and 0.78 respectively) with reference laboratories for a total of 1,608 determinations. The highest rate of inaccurate diagnoses occurred in positive samples of very low antibody concentration (40% for syphilis and 11.9% for HIV). The stability tests showed that titers were stable for up to one week at 30°C in dry conditions.
Conclusion The results show that errors in the interpretation of POC test results were identified by the EQA programme using DTS. The use of POC tests for syphilis and HIV is now recommended as a policy by the Brazilian government. EQA/using DTS can help to improve the quality of these screening programmes and is already being implemented nationally.
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