Do the HIV antibody EIA and HIV antibody Western blot test for HIV-1 and HIV-2?
A. There are two types of HIV, HIV-1 and HIV-2. Both HIV-1 and HIV-2 have been identified in the United States. The number of known HIV-2 infected persons in the U.S. is less than 100. The estimated number of people in the U.S. infected with HIV-1 is between 650,000 and 900,000. Q. How accurate are HIV antibody tests in detecting the various subtypes of HIV-1? A. HIV-1 is divided into two groups of subtypes. These two groups are referred to as Group M (major) and Group O (outlier). HIV-1 subtypes of Group M vary, depending on their genetic structure. These include subtypes A through I. In the United States, the predominate HIV-1 subtype is B. Most antibody tests for detecting HIV-1 were developed with the B subtype of the virus. As the genetic composition of a particular virus diverges from the B subtype, the likelihood that the test will be accurate decreases. Most tests, however, do appear to be able to detect antibody to most strains. There are many reasons for a false-positive EIA
