AIDS testing in the 1990s

Abstract

The principal screening tests for HIV infection are serologic assays for viral-specific antibody. The most commonly used tests are either enzyme immunoassays or enzyme-linked immunosorbent assays. The sensitivity of these tests is approximately 98%; the specificity is almost 100%. The Western blot is presently the definitive confirmatory test for HIV infection. To be considered positive, the assay must show reactivity to three specific viral proteins: p24 (“gag”), p31 (“pol”), and either gp41, gp120, or gp160 (“env”). The specificity of the Western blot is essentially 100%. Other diagnostic tests for HIV infection include direct detection of viral antigen by polymerase chain reaction and viral culture. Virus is cultured most readily from peripheral blood lymphocytes and monocytes. These latter methods are not available as readily and are not as inexpensive as antibody detection assays and, thus, are not widely used in daily clinical practice.