Following are three types of HIV tests. If the first test is positive, a follow-up test is necessary to validate the result.

Antibody Test : Detects the presence of antibodies against HIV, which typically develop within two to eight weeks after exposure to the virus. An antibody test can be conducted on a sample of blood or oral fluid.

Combination Antigen-Antibody Test: Detects both the antibody to HIV and the antigen “p24” – a protein that is part of the virus itself. Because the p24 antigen can be detected within four to seven days before antibodies appear, combination tests can also identify very early infections.

RNA Test : Detects the presence of the virus in the blood. An RNA test can detect very early infection, within 10-15 days of exposure, before antibody tests are able to detect HIV.