The HIV-1 genotype and phenotype resistance testing are part of the diagnostic-therapeutic tools currently available for the management of HIV patients. They are used to determine therapeutic alternatives after treatment failure for patients previously treated with highly active antiretroviral therapy (HAART) or in special cases for patients recently infected who meet selection criteria (pregnant women infected with HIV of unknown source in areas of resistant HIV strains; patients without antiretroviral treatment infected from HIV positive patients with known therapeutic drug failure).Drug failure is defined as any viral load detected in two occasions, measured at least two weeks apart, in patients with previously undetected viral loads; or an increase of 0.5 log in the viral load of patients who have never had undetectable viral load.