1. Treat Asia Quality Assurance Scheme Supported by AMFAR and coordinated by the National Reference Laboratory in Australia Sally Land.

2. A Quality Assessment Scheme to Standardize the Outcome of HIV Genotypic Drug Resistance Testing in a group of Asian Laboratories Sally Land 1, Philip Cunningham 2, Jialun Zhou 2, Kevin Frost 3, David Katzenstein 4, Rami Kantor 5, Allison DeLong 5, David Sayer 6, Jeffery Smith 3, Elizabeth M Dax 1 and Matthew Law 2 on behalf of the TAQAS Laboratory Group. 1 National Serology Reference Laboratory, Australia, Melbourne, Victoria, Australia; 2 The National Centre in HIV Epidemiology and Clinical Research, Sydney, Australia; 3 The Foundation of AIDS Research, New York, NY, USA; 4 Stanford University, Stanford, CA, USA; 5 Brown University, Providence, RI, USA; and 6 Conexio Genomics, Fremantle, W.A., Australia.

7. 9 panels in 23 labs, % detection

10. 0 20 40 60 80 100 % Viral mixtures detected TAQAS 1 TAQAS 2 TAQAS 3 TAQAS 4 Lab ID 1 – 10 Lab ID 1 – 11 Lab ID 1 – 11 Lab ID 1 - 16

11. Participants demonstrated high level agreement at the nucleotide sequence level that was consistent with that reported in the literature (Figure 1) (5). Participants maintained a high level of detection of DRMs that was consistent with the level of detection achieved in other EQAS (Figure 2) (6). Participants’ detection of viral mixtures varied and correlated with detection of DRMs (Pearson’s r: p<.05), therefore ability to detect viral mixtures reflects, to a certain degree, the quality of testing (Figure 3). Participants’ detection of viral mixtures may be influenced by the proportion of DRMs present as mixtures of mutant and wild type virus, nucleotide sequence quality and sequence editing. Agreement in interpretation of ARV susceptibility may be increased when all participants use the same system.