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The development and subsequent licensure by the U.S. Food and Drug Administration (FDA) of enzyme immunoassays (EIA) for human immunodeficrency virus (HIV) antibody provided a low-cost test that was well suited for diagnosis, mass screening of populations, and testing blood donations for HIV infection. Each year the number of tests performed as well as the number of laboratories performing tests increases in the United States, but programs for quality control (QC) of laboratory testing have not kept pace. Standard panels of serum for quality control and evaluation of EIA and western blot tests are not generally available. Quality control programs for serologic tests are crude compared to the sophisticated computer-driven programs used in clinical chemistry laboratories. In fact, some serology laboratories do no more than run the controls supplied by the kit manufacturer. Some serology laboratories, however, have adapted the QC procedures similar in design to those used for clinical chemistry to monitor testing for HIV infections. This chapter will describe these adaptations and recommend a simple and inexpensive system for quality control of HIV tests.

Persons infected with the human immunodeficiency virus (HIV) have a spectrum of clinical features, ranging from persons who are infected but appear completely healthy to those with rapid disease progression and mortality. All groups, regardless of clinical stage, possess several biologic indicators of viral infection or replication (Figure 5.1). These include viremia, antibodies against viral proteins, circulating viral proteins, and nonspecific markers such as neopterin, beta2-microglobulins, and T4 cell counts. A variety of immunologic tests currently exists for the detection of viral antibodies and protein antigens. These assays have permitted testing programs to protect the blood supply from infected units and to conduct seroprevalence surveys to define the epidemic. More recently, the presence or absence of viral and nonspecific markers have been used to predict the onset of clinical disease.