Acute human immunodeficiency testing and linkage to Care: An evaluation of community-based 4th generation antigen/antibody testing

As a relatively novel testing algorithm, the experience with 4th generation HIV testing and linkage to care outcomes is limited. The purpose of this study is to report descriptive outcomes regarding patients with acute HIV infection who received antigen/antibody (Ag/Ab) reactive results and linkage to care services. HIV testing and linkage data from four AIDS Healthcare Foundation (AHF) Wellness Centers in Los Angeles County, CA were retrospectively reviewed from January 15, 2016 to May 26, 2018. Patients were screened using the INSTI® HIV-1/HIV-2 Rapid Antibody Test (bioLytical, Richmond, BC). A negative result reflexed to an HIV test on the Abbott Architect Ag/Ab Assay (Abbott Laboratories, Lake Bluff, IL). Out of the total 11,173 patient specimens processed on the Architect platform, 56 received preliminary reactive results and 42 returned for confirmatory viral load testing. Twenty-seven (64%) of the 42 patients were confirmed to be acutely infected with HIV. All 27 patients acutely infected with HIV were linked into care: 22 were linked into AHF’s primary care and the remaining five sought care with a primary care provider external to AHF. Despite low positivity, the 27 acutely HIV-infected patients would have otherwise been missed if the patients had only received the standard-of-care rapid antibody test. Curbing HIV incidence in the United States will require multiple innovative approaches. Detecting acute infections through 4th generation testing is one of the many valuable tools that organizations can utilize in the new decade. Key words: Acute HIV infection, testing algorithms, linkage to care, HIV antigen and antibody combination test, HIV antigen and antibody combination test, Abbott Architect.