Diagnostic tests of HIV infection and AIDS

Abstract

Background: Human immunodeficiency virus (HIV) infection presents a major global health challenge. According to the World Health Organization, approximately 39.0 million people have HIV, as of 2022, with 1.3 million new infections annually. In Korea, the first HIV cases were reported in 1985, and the number of cases has increased continuously since 1988. In 2022, 1,066 cases were newly diagnosed, increasing the total number of cases to approximately 15,880.Current Concepts: Diagnostics play a crucial role in the management of HIV, for early diagnosis and initiation of antiretroviral therapy. Approval of the first HIV antibody test in 1985 by the US Food and Drug Administration marked a notable advance in the ability to diagnose HIV infection. The screening test for HIV infection typically consists of a two-step approach, in which a fourth-generation combination HIV-1/2 immunoassay is followed by a confirmatory Western blot. Despite its high accuracy for chronic infections, the window period and the early-stage of HIV infections are problematic, and populations with low HIV prevalence show a low positive predictive value. A false positive result can occur from blood transfusions, vaccinations, and autoantibodies. Novel diagnostic tools, such as nucleic acid testing for viral RNA/DNA and antigen testing for p24 antigen have reduced the window period, allowing for earlier detection and differentiation between HIV-1 and HIV-2. Pointof-care tests are beneficial in resource-limited settings although their lower sensitivity and specificity require additional confirmatory follow-up testing.Discussion and Conclusion: In this review, we provide a historical perspective on the evolution of HIV diagnostics (serological and molecular) and describe the roles of conventional and point-of-care testing within the laboratory diagnostic network.