HIV test: A test for the human immunodeficiency virus, the cause of AIDS. HIV tests are designed to detect antibodies to the HIV virus or the HIV virus itself.

The antibody tests are:

• ELISA (enzyme-linked immunosorbent assay): a screening test used to detect infection with HIV. If positive, the ELISA test is usually repeated.
• Western blot: a test usually used to confirm the results of an ELISA. It can rule out a false-positive by distinguishing HIV antibodies from other antibodies that may react to the ELISA.
• IFA (indirect fluorescent antibody): a test used like the less expensive Western blot to confirm the results of an ELISA.

The premiere test that can identifies the genetic material, the RNA, of the HIV virus is called PCR (the polymerase chain reaction). PCR can detect an early HIV infection before antibodies are evident and determine whether a baby born to an HIV-positive mother will have HIV. A test similar to PCR testing, called the branched DNA test, also detects the RNA of HIV.