Pearls and Pitfalls of HIV-1 Serologic Laboratory Testing

Detection of HIV-specific antibodies forms the corner stone for laboratory diagnosis of HIV infections. Serologic methods are routinely used to determine whether a host is infected with HIV, to evaluate the status of infections, and to assist monitoring antiretroviral therapy. Primary diagnosis of HIV infection is commonly accomplished by serology via detection of HIV antibody using a screening enzyme immunoassay (EIA) or a rapid assay, followed by a subsequent confirmatory Western blot (WB) test. Used in a point of care testing (POCT) format, rapid HIV antibody tests have filled an essential need in HIV testing especially in resource-limited settings. Detuned antibody assays allow for the distinction between recent and distant HIV-1 infections, which have been used mainly for epidemiology surveillance and investigations. In addition to clinical diagnosis of HIV infection, serology remains the mainstay for screening donated blood and blood products prior to transfusion to ensure that recipients receive the safest possible blood products. In this chapter, we will review pearls and pitfalls of serologic methods currently being used in routine HIV diagnosis and screening. Rational use of HIV serologic testing will be illustrated by clinical case presentations.