Acquired Immune Deficiency Syndrome - HIV

How is the disease diagnosed?

The body produces antibodies to fight off HIV infection. HIV is usually diagnosed by blood tests called antibody titer tests. The enzyme immunoassay, or EIA, is used as a screening test. If this test is positive, a HIV Western blot test is done to confirm the diagnosis. The virus can also be detected by testing for viral proteins and by doing blood cultures. Other tests may be ordered to help diagnose complications of HIV infection, such as pneumonia.

Negative tests do not always mean that a person is free of infection. Weeks or months might pass after exposure to the virus before antibodies can be detected in the body.