Test Details: HIV (human immunodeficiency virus) is a virus that attacks the immune system, the body's natural defence system. HIV infects and destroys certain white blood cells called CD4+ cells. There are two types of HIV: 1. HIV-1, which causes almost all the cases of AIDS worldwide. 2. HIV-2, which causes an AIDS-like illness. A Western blot test is typically used to confirm a positive HIV diagnosis. During the test, a small sample of blood is taken and it is used to detect HIV antibodies, not the HIV virus itself. The Western blot test separates the blood proteins and detects the specific proteins (called HIV antibodies) that indicate an HIV infection. The Western blot is used to confirm a positive ELISA and the combined tests are 99.9% accurate.