Identification of acute HIV infection using fourth-generation testing in an opt-out emergency department screening program

Study objective: Acute HIV infection is a clinical diagnosis aided by technology. Detecting the highly infectious acute stage of HIV infection is critical to reducing transmission and improving long-term outcomes. The Maricopa Integrated Health System implemented nontargeted, opt-out HIV screening with a fourth-generation antigen/antibody combination HIV assay test in our adult emergency department (ED) at Maricopa Medical Center to assess the prevalence of both acute and chronic unrecognized HIV.

Methods: Eligible patients aged 18 to 64 years were tested for HIV if they did not opt out and had blood drawn as part of their ED care. Patients were not eligible if they had a known HIV or AIDS diagnosis, exhibited altered mental status, were a current resident of a long-term psychiatric or correctional facility, or prompted a trauma activation. Reactive test results were delivered by a physician with the assistance of a linkage-to-care specialist. Specimens with a reactive fourth-generation assay result underwent confirmatory testing.

Results: From July 11, 2011, through January 5, 2014, 27,952 HIV screenings were performed for 22,468 patients tested for HIV; 78 (0.28%) had new HIV diagnoses. Of those, 18 (23% of all new diagnoses) were acute HIV infections, and 22 patients (28%) had a CD4 count of less than 200 cells/mL, or an opportunistic infection.

Conclusion: HIV testing with a fourth-generation antigen/antibody laboratory test producing rapid results is feasible in an ED. Unexpectedly, nearly one fourth of patients with undiagnosed HIV had acute infections, which would have been more difficult to detect with previous testing technology.