Approximately 1500-2000 subjects in total will be enrolled in the study across all sites, into three different study populations. Population 1 will be comprised of at least 500 subjects from a population at risk of infection with HIV. Population 2 will be comprised of at least 500 subjects that are known HIV positive individuals. Population 3 will be comprised of at least 500 subjects from a population at low risk of HIV infection. Reveal G4 will be used to test fingerstick whole blood and venous whole blood samples from all study subjects. For enrolled subjects in Populations 1 and 3, who are of unknown HIV antibody status, a plasma sample prepared from the venous whole blood sample will also be tested with an algorithm of FDA-approved assays for the detection of HIV-1 antibodies. For Population 2 subjects who are known HIV-positive individuals, results of previous HIV tests will be obtained from the subjects' medical records. The sensitivity and specificity of Reveal G4 will be determined in fingerstick and venous whole blood relative to HIV-1 antibody status as determined by an algorithm of FDA-approved assays.