HIV-1 drug resistance genotyping quality assessment: Results of the ENVA7 Genotyping Proficiency Programme

BackgroundDrug-resistance testing plays a critical role in selection of optimal treatment regimens for HIV infected individuals. Laboratories performing testing must implement quality control measures including external quality assessment.ObjectivesThe ENVA7 Programme (2007) was organised by QCMD to assess the performance of laboratories testing for drug-resistance mutations in the HIV-1 Protease and Reverse Transcriptase genes.Study designThe ENVA7 panel consisted of 5 lyophilised plasma samples (HIV-1 subtypes B, C and F). The viruses harboured wild type or resistant genotypes at various positions of the PR and RT genes. All IAS-defined resistance-associated codons were scored in comparison to the consensus sequence for each sample using a scoring system developed to allow simple and standardised comparisons between laboratories and/or technologies.Results111 laboratories from 44 countries participated of which 95 submitted 98 datasets. 36 datasets were generated using ViroSeq (Abbott), 27 using TruGene (Siemens) and 35 using in-house assays.ConclusionsAll technologies successfully genotyped each of the panel samples, irrespective of the virus subtype. While the assays for genotypic HIV drug-resistance determination have evolved into reliable and technically capable procedures of generating high quality results, variation in the quality of results is still observed between laboratories.