Related Experiment Video
Updated: Apr 15, 2026
The α-test: Rapid Cell-free CD4 Enumeration Using Whole Saliva
Published on: May 16, 2012
Determination of HIV Status in African Adults With Discordant HIV Rapid Tests
Jessica M Fogel1, Estelle Piwowar-Manning, Kelsey Donohue
1*Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD; †Program in Global Health, University of California, Los Angeles, Los Angeles, CA; ‡Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA; §Department of Global Health, University of Washington, Seattle, WA; ‖Department of Probability and Statistics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic; ¶Muhimbili University of Health and Allied Sciences, Muhimbili University Teaching Hospital, Dar es Salaam, Tanzania; #DST-NRF Centre of Excellence in Human Development, Universities of the Witwatersrand and KwaZulu-Natal, Johannesburg, South Africa; **Human Sciences Research Council, Durban, South Africa; ††Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, University of the Witwatersrand, Johannesburg, South Africa; ‡‡South African Medical Research Council, Cape Town, South Africa; §§Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, SC; and ‖‖Center for World Health, David Geffen School of Medicine and UCLA Health, Los Angeles, CA.
Background:
In resource-limited settings, HIV infection is often diagnosed using 2 rapid tests. If the results are discordant, a third tie-breaker test is often used to determine HIV status. This study characterized samples with discordant rapid tests and compared different testing strategies for determining HIV status in these cases.
Methods:
Samples were previously collected from 173 African adults in a population-based survey who had discordant rapid test results. Samples were classified as HIV positive or HIV negative using a rigorous testing algorithm that included two fourth-generation tests, a discriminatory test, and 2 HIV RNA tests. Tie-breaker tests were evaluated, including rapid tests (1 performed in-country), a third-generation enzyme immunoassay, and two fourth-generation tests. Selected samples were further characterized using additional assays.
Results:
Twenty-nine samples (16.8%) were classified as HIV positive and 24 of those samples (82.8%) had undetectable HIV RNA. Antiretroviral drugs were detected in 1 sample. Sensitivity was 8.3%-43% for the rapid tests; 24.1% for the third-generation enzyme immunoassay; 95.8% and 96.6% for the fourth-generation tests. Specificity was lower for the fourth-generation tests than the other tests. Accuracy ranged from 79.5% to 91.3%.
Conclusions:
In this population-based survey, most HIV-infected adults with discordant rapid tests were virally suppressed without antiretroviral drugs. Use of individual assays as tie-breaker tests was not a reliable method for determining HIV status in these individuals. More extensive testing algorithms that use a fourth-generation screening test with a discriminatory test and HIV RNA test are preferable for determining HIV status in these cases.
