Worldwide evaluation of DNA sequencing approaches for identification of drug resistance mutations in the human immunodeficiency virus type 1 reverse transcriptase

A panel (ENVA-1) of well-defined blinded samples containing wild-type and m utant human immunodeficiency virus type 1 (HIV-1) reverse transcriptase was analyzed by automated DNA sequencing in 23 laboratories worldwide. Drug re sistance mutations at codons 41, 215, and 183 were present in the panel sam ples at different ratios to the wild type. The presence of mutant genotypes was determined qualitatively and quantitatively, All laboratories reported the presence of sequence heterogeneities at codons 41, 215, and 184 in one or more of the panel samples, though not all reported the correct codon ge notypes. Two laboratories reported a mutant genotype in samples containing only the wild type, whereas two and three laboratories failed to detect the mutant genotypes at codons 41 and 215, respectively, in a completely mutan t DNA population, Mutations present at relative concentrations of 25% of th e total DNA population were successfully identified by 13 of 23, 10 of 23, and 16 of 23 labs for codons 41, 215, and 184Val, respectively, For more th an 80% of those laboratories that qualitatively detected the presence of a mutation correctly, the estimated wild type/mutant ratio was less than 25% different from the input ratio in those samples containing 25 to 50% or 75% mutant input. This first multicenter study on the quality of DNA sequencin g approaches for identifying HIV-1 drug resistance mutations revealed large interlaboratory differences in the quality of the results, The application of these procedures in their current state would in several cases lead to inaccurate or even incorrect diagnostic results, Therefore, proper quality control and standardization are urgently needed.