Blinded, multicenter comparison of methods to detect a drug-resistant mutant of human immunodeficiency virus type 1 at low frequency.

We determined the abilities of 10 technologies to detect and quantify a common drug-resistant mutant of human immunodeficiency virus type 1 (lysine to asparagine at codon 103 of the reverse transcriptase) using a blinded test panel containing mutant-wild-type mixtures ranging from 0.01% to 100% mutant. Two technologies, allele-specific reverse transcriptase PCR and a Ty1HRT yeast system, could quantify the mutant down to 0.1 to 0.4%. These technologies should help define the impact of low-frequency drug-resistant mutants on response to antiretroviral therapy.