Outcomes of discordant HIV screening test results at a southern academic medical center

Abstract

Objective: The aim of this study was to examine outcomes of follow-up for persons with discordant fourth-generation HIV screening test results. Design: A retrospective chart review. Methods: We analyzed the electronic health record at the Medical University of South Carolina for a 10-year period spanning 2012–2022 to identify instances of discordant HIV screening test results, wherein initial antigen/antibody screening was positive, but reflex confirmatory testing for HIV-1 and HIV-2 antibodies was negative. We reviewed individual records to evaluate clinical follow-up and determine if the discordant test represented an acute HIV infection, a false-positive result, or was unresolved. Results: We identified 199 testing instances with discordant results. Most discordant results (n = 115) were subsequently determined to reflect a false-positive test, while 56 were unresolved without documented follow-up testing. Twenty-eight cases of acute HIV infection were identified of which 26 were linked to care within a month of initial testing. Two acute HIV cases were not identified in real time leading to delay in diagnosis and care. Testing done in the context of infectious symptoms and testing performed in the emergency department were associated with increased odds of a discordant test ultimately reflecting acute HIV infection. Conclusion: These results demonstrate the importance of appropriate and timely follow-up for discordant HIV screening test results.