The standard screening “HIV test” used in clinics or Emergency Departments works to detect human antibodies to HIV. While the test can provide quick-and-easy results, a significant drawback has been the inability to detect early HIV infections. In the acute or early phase of HIV infection, the body does not yet produce antibodies to the virus; consequently, the HIV-infected individual may still appear “HIV-negative”. There are PCR-based methods to detect HIV nucleic acids, but these have a longer turnaround time and are not cost-effective for routine screening.

To circumvent the problem of false negative results early in an infection, the Architect HIV Ag/Ab Combo Assay (Abbott Laboratories) was designed to detect both HIV antigen (p24) and antibody. It is the first of its kind and is also intended for diagnosis of both HIV-1 and HIV-2 infections. The assay was just approved for clinical use by the U.S. Food and Drug Administration. It is not intended for routine screening of blood donors, except in urgent situations.