Human Immunodeficiency Viruses

Abstract

Human immunodeficiency viruses (HIVs) are enveloped plus‐stranded RNA viruses. HIV viruses are classified based on phylogenetic relatedness of nucleotide sequences. Serum and plasma are the most common specimen types used for routine HIV antibody and antigen determinations in the laboratory. Because HIV can be isolated from the blood of the majority of HIV‐infected individuals, HIV culture was frequently utilized in the early years of the epidemic as a diagnostic or prognostic marker or for assessing the efficacy of antiviral therapy. Nucleic acid tests are needed for infant diagnosis because serologic tests are not useful for the detection of HIV infection in infants; maternal antibodies can persist in uninfected, HIV‐exposed infants until 18 months of age. Genotyping and variant calling information can identify nonsynonymous nucleotide mutations, termed drug resistance mutations, that code amino acid changes which can reduce the susceptibility of HIV to antiretroviral drugs.