The US Food and Drug Administration approved Bio-Rad Laboratories' BioPlex 2200 HIV Ag-Ab assay, which differentiates between HIV-1 antibodies, HIV-2 antibodies, and HIV-1 p24 antigen in human serum or plasma specimens.

Two major types of HIV have been identified: HIV-1 and HIV-2. HIV-1 is responsible for most HIV infections throughout the world. HIV-2 is found primarily in West Africa; however, cases of HIV-2 infection have been identified in the United States. HIV-1 and HIV-2 are similar, but distinct viruses.

The BioPlex 2200 HIV Ag-Ab assay is to aid in the diagnosis of infection with HIV-1 and/or HIV-2, including acute HIV-1 infection. It may be used in adults, children two years of age and older, as well as in pregnant women. The assay may also be used to screen organ donors for HIV-1/2 when the blood specimen is collected while the donor’s heart is still beating. However, the assay is not approved for use in screening blood or plasma donors, except in urgent situations where traditional licensed blood donor screening tests are unavailable or their use is impractical.

“Today’s approval provides healthcare professionals another option for the diagnosis of HIV infections,” said Karen Midthun, M.D., director of the FDA’s Center for Biologics Evaluation and Research. “The ability to diagnose HIV infection early and differentiate between types of infection is important in the care of individuals as both diseases exhibit the same symptoms but progress at different rates.”

HIV antigens and antibodies appear and are detectable at different stages of the infection. Early in the infection, HIV-1 antigen can be detected prior to the development of detectable levels of HIV-1 antibodies. Acute HIV-1 infection is identified when the blood specimen is positive for HIV-1 p24 antigen but is negative for HIV-1 and HIV-2 antibodies.

The BioPlex 2200 HIV Ag-Ab assay allows results of antigen and antibody detection to be reported separately. In addition to distinguishing between established HIV-1 and HIV-2 infection, reporting of distinct results helps differentiate between acute and established HIV infection respectively.

The BioPlex 2200 HIV Ag-Ab assay is intended for use with the BioPlex 2200 System, which was cleared by the FDA in 2004.