Laboratory methods in the diagnosis and prognostic staging of infection with human immunodeficiency virus type 1.

Laboratory evaluation of infection with human immunodeficiency virus type 1 (HIV-1) may involve detection of antibodies to HIV-1, direct detection of HIV-1 itself, and measurement of an individual's immunologic status at the time of presentation. The ELISA is currently the preferred initial screening test, although a variety of other rapid immunoassays have also been developed. Methods defining the antigenic specificity of the antibody response, such as the western blot, have become standard confirmatory tests in this setting. CD4+ cell enumeration and the HIV-1 antigen capture assay are useful in predicting the course of HIV-1 infection and in monitoring antiretroviral therapies. Newer techniques of HIV-1 co-cultivation permit the characterization of viral isolates and the stratification of patients and facilitate monitoring of the effects of antiretroviral agents. The polymerase chain reaction is of value in identifying HIV-1 infection in individuals with inconclusive serologic results. Judicious use of other laboratory tests, including surrogate markers such as beta 2-microglobulin, also provides prognostic information potentially useful in clinical management of HIV-1-infected patients.