Indeterminate and discrepant rapid HIV test results in couples' HIV testing and counselling centres in Africa

• Type of Material: Article
• Authors: Debrah I. Boeras, Emory University; Nicole Luisi, Emory University; Etienne Karita, Projet San Francisco; Shila McKinney, Emory University; Tyronza Sharkey, Zambia Emory HIV Research Project; Michelle Keeling, Zambia Emory HIV Research Project; Elwyn Chomba, Zambia Emory HIV Research Project; Colleen Kraft, Emory University; Kristin Wall, Emory University; Jean Bizimana, Projet San Francisco; William Kilembe, Zambia Emory HIV Research Project; Amanda Tichacek, Emory University; Angela M. Caliendo, Emory University; Eric Hunter, Emory University; Susan Allen, Emory University
• Language: English
• Date: 2011-04-08
• Publisher: Wiley Open Access
• Publication Version: Final Published Version
• Copyright Statement: © 2011 Boeras et al; licensee BioMed Central Ltd.
• License: Creative Commons Attribution 2.0 Generic
• Final Published Version (URL): http://dx.doi.org/10.1186/1758-2652-14-18
• Title of Journal or Parent Work: Journal of the International AIDS Society
• ISSN: 1758-2652
• Volume: 14
• Issue: 1
• Start Page: 18
• End Page: 18
• Grant/Funding Information: This study was funded by grants NIAID R01 23980, R01 40951, R01 51231, NICHD R01 40125, NIMH R01 66767, FIC D43 TW001042, the Bill & Melinda Gates Foundation Grand Challenges Program (#37874), and the International AIDS Vaccine Initiative.; This work was supported in part by the Virology Core at the Emory Center for AIDS Research (P30 AI050409).
• Keywords: RWANDA; Immunology; Science & Technology; ZAMBIA; Life Sciences & Biomedicine; Infectious Diseases; SEROCONVERSION; HUMAN-IMMUNODEFICIENCY-VIRUS; VIRAL LOAD; INFECTION; DISCORDANT COUPLES; TYPE-1; UNITED-STATES; IMMUNE CONTROL
• Research Categories: Health Sciences, Immunology

Abstract

Background: Many HIV voluntary testing and counselling centres in Africa use rapid antibody tests, in parallel or in sequence, to establish same-day HIV status. The interpretation of indeterminate or discrepant results between different rapid tests on one sample poses a challenge. We investigated the use of an algorithm using three serial rapid HIV tests in cohabiting couples to resolve unclear serostatuses. Methods. Heterosexual couples visited the Rwanda Zambia HIV Research Group testing centres in Kigali, Rwanda, and Lusaka, Zambia, to assess HIV infection status. Individuals with unclear HIV rapid antibody test results (indeterminate) or discrepant results were asked to return for repeat testing to resolve HIV status. If either partner of a couple tested positive or indeterminate with the screening test, both partners were tested with a confirmatory test. Individuals with indeterminate or discrepant results were further tested with a tie-breaker and monthly retesting. HIV-RNA viral load was determined when HIV status was not resolved by follow-up rapid testing. Individuals were classified based on two of three initial tests as "Positive", "Negative" or "Other". Follow-up testing and/or HIV-RNA viral load testing determined them as "Infected", "Uninfected" or "Unresolved". Results: Of 45,820 individuals tested as couples, 2.3% (4.1% of couples) had at least one discrepant or indeterminate rapid result. A total of 65% of those individuals had follow-up testing and of those individuals initially classified as "Negative" by three initial rapid tests, less than 1% were resolved as "Infected". In contrast, of those individuals with at least one discrepant or indeterminate result who were initially classified as "Positive", only 46% were resolved as "Infected", while the remainder was resolved as "Uninfected" (46%) or "Unresolved" (8%). A positive HIV serostatus of one of the partners was a strong predictor of infection in the other partner as 48% of individuals who resolved as "Infected" had an HIV-infected spouse. Conclusions: In more than 45,000 individuals counselled and tested as couples, only 5% of individuals with indeterminate or discrepant rapid HIV test results were HIV infected. This represented only 0.1% of all individuals tested. Thus, algorithms using screening, confirmatory and tie-breaker rapid tests are reliable with two of three tests negative, but not when two of three tests are positive. False positive antibody tests may persist. HIV-positive partner serostatus should prompt repeat testing.