Antiretroviral resistance testing for clinical management

The advent of highly active antiretroviral therapy (HAART) has dramatically changed the management of HIV disease. These powerful regimens of drugs have reduced morbidity and mortality as well as number of hospitalizations among individuals with HIV. Nevertheless, many patients fail to achieve viral suppression. Various factors underlie this problem, but resistance to current medications has been increasingly recognized as an important element. Several methods of assessing antiretroviral resistance in HIV-1 are currently available. Phenotype assays directly assess the level of susceptibility of a virus to specific drugs. Genotype assays determine the presence of viral mutations that may affect viral susceptibility to a particular drug or class of drugs. An increasing amount of data indicates that antiretroviral resistance testing may improve response to therapy and increase the likelihood of achieving viral suppression. In this paper we review the available data regarding the role of antiretroviral resistance testing and compare the two different assays. We also discuss limitations of the current assays, interpretation of the data, and current consensus guidelines. Although many questions remain, antiretroviral resistance testing along with expert opinion can aid in the management of HIV disease.