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P16.31 Improving timely hiv results in key populations: rapid test antibody evaluation for hiv diagnosis in guatemala, 2012–2013
  1. E Arana Flora1,
  2. L Castillo-Signor2,
  3. P Marchorro2,
  4. V Girón3,
  5. A Lopez2,
  6. C Escobar2,
  7. C Vargas1,
  8. R Mendizabal-Burastero1,
  9. S Morales-Miranda1
  1. 1HIV Unit, Centers for Health Studies, Del Valle University
  2. 2National Health Laboratory, Ministry of Health, Guatemala
  3. 3HIV National Program, Ministry of Health, Guatemala

Abstract

Introduction Guatemala has a concentrated HIV epidemic among key populations; in 2003, the first rapid test validation in Central America was performed. A national HIV testing algorithm with a rapid test and a second test using an enzyme immunoassay (EIA) was developed (average turnaround time of 2 weeks). Given the changes in the market since 2003, we present results of a second rapid test validation to update the Guatemalan algorithm.

Methods Validation was performed in 2012–2013, evaluating a total of 10 rapid tests in two phases: 1) with serum, HIV-negative samples were obtained from blood banks, and positive samples from HIV care units; 2) with whole blood, negative samples were obtained from antenatal care services and positive samples from HIV care units. We tested 452 serum samples [244 HIV+, 208 HIV-] and 432 whole blood samples (10 HIV positive, 422 HIV negative) using two EIA (Roche ELECSYS HIV Combi and Abbott AXSYM HIV Ag/Ab Combo). Discordant results were evaluated with HIV-1 Western Blot. For fourth generation rapid tests, only antibody was evaluated. Data was analysed using OpenEpi.

Results Six HIV rapid tests were included for both phases. All tests (except Double Check Gold) reported sensitivity higher than 99% and specificity higher than 95%. Determine HIV 1/2 and HIV Ag/Ab reported the highest results for sensitivity (100%). Hexagon HIV (100%) and Accu-Tell (99.5%) reported the highest results for specificity. All rapid tests that also included HIV-2 detection, showed cross-reactivity, ranging from 37% of HIV cases for Anarapid HIV 1/2/O Tri-line to 15% for Rapid HIV 1/2/O Tri-Line.

Conclusion Our results show that Determine HIV½ and HIV Ag/Ab should be recommended as a screening test while Hexagon HIV and Accu-Tell should be recommended as second test. Rapid test validation provides valuable information for on-site confirmation of reactive results improving diagnosis turnaround time.

Disclosure of interest statement We declare that we have no conflicts of interest.

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