HIV update. Diagnostic tests and markers of disease progression and response to therapy.

HIV-1 infection continues to present diagnostic and management challenges on a global scale. Multiple testing strategies currently are used for evaluation of patients and infection status. Serologic testing represents the standard for diagnosis of HIV-1 infection. Molecular methods enable screening of the blood supply, detection of vertical transmission, and viral load testing to monitor patients during therapy. Molecular resistance testing facilitates the assessment of viral quasi species and the presence of specific mutations that confer antiviral resistance. Both genotyping and phenotyping approaches have been adopted for HIV-1 drug-resistance testing and enable rational modification of therapies for patients in whom their current regimens are failing.