Verification of False Reactivity in HIV Rapid DiagnosticTests and Its Translation Into the Three Tests Algorithmin Cameroon

Rogers Ajeh Awoh at all

Abstract

Background: In a context of HIV seropositivity below 5%, transitioning from a two-to
a three-test algorithm is required to secure positive predictive values > 99% for mitigating false reactivity. With Cameroon having 2.7% seroprevalence, we sought to
ascertain events of false reactivity from eight WHO-prequalified HIV rapid diagnostic tests (RDTs) and design suitable combinations for the country three-test algorithm.
Methods: A facility-based study was conducted in July–August 2021 among 172 consenting clients attending health facilities in Yaoundé-Cameroon. Whole blood was collected and samples characterized in parallel using KHB Diagnostic Kit for HIV (1 + 2)
Antibody and INNO-LIA HIV I/II Ag/Ab to rule out reactive cases. Two lots of each selected RDT were tested simultaneously in quadruplicate on HIV non-reactive
samples and repeated by a different tester. RDTs were considered false positive if any reactivity was detected.
Results: Following characterization, 25 samples were HIV-reactive (i.e., ruled out) and 147 non-reactive. Following random selection, 100 non-reactive samples tested for false reactivity revealed: 0% (0/100) First Response HIV 1–2-O Card, 0% (0/100) First Response HIV1 + 2/Syphilis Combo, 0% (0/100) STANDARD Q HIV/Syphilis Combo, 0% (0/99) ONE STEP Anti-HIV1& 2 (one invalid result); 1% (1/100) Determine HIV Early Detect and Bioline HIV/Syphilis Duo, 2% (2/100) Alere Determine HIV-1/ 2, 4%
(4/100) Rapid Test for Antibody to HIV.
Conclusion: In the Cameroonian context, HIV false reactivity ranged from 0% to 4% across selected RDTs. Thus, a reliable three-test algorithm ranks First Response HIV 1–2-0
Card, First Response HIV1 + 2/Syphilis Combo or STANDARD Q as suitable RDT-1 tomitigate false-positive events at the country-level.