Dentified them as R5. The phenotype of the discordant samples showed that MiSeq correctly predicted the tropism of four of the five samples (samples 29, 30, 41 and 45). We also evaluated the capacity of the MiSeq and 454 GS-Junior systems to accurately quantify CXCR4-using variants by comparing the percentages of X4 variants in 11 samples with concordant detection of X4 variants (Table 2). The MiS