Serological diagnosis of human immunodeficiency virus infection by Western blot testing. The Consortium for Retrovirus Serology Standardization

THE ACQUIRED immunodeficiency syndrome (AIDS) epidemic and the increasing concern of both the public and governmental agencies about the testing of low-risk populations for AIDS have created an unprecedented demand for serological testing for human immunodeficiency virus (HIV). Although the enzyme immunoassay for HIV antibodies was originally developed to screen donated blood, it is now routinely used as a diagnostic tool in the workup for HIV infection. Unfortunately, the exquisite sensitivity of the enzyme immunoassay, coupled with less than 100% specificity, creates a potential for falsely positive reactions. This feature means the test has a relatively poor positive predictive value for populations with a low prevalence of HIV infections.1Supplemental or confirmatory tests that are specific enough to distinguish between the falsely positive results of the screening test and the truly positive ones must be used. Various laboratory assays offering greater specificity, including the Western blot test,2,3indirect