We assessed concordance between our results expressed as the FC provided and the FC generated using alternative phenotypic methods, namely the Virco TYPE HIV-1 test and the in vitro Antivirogram assay for both drugs. Significant correlations were observed between the Virco TYPE HIV-1 phenotypic score interpreted with the Stanford HIVdb v6.0.8 algorithm was compared with that obtained using our FC, a significant correlation was observed between both parameters (P,0.0001, Spearman’s r¼0.69) (Figure 2e). These results show that the phenotypic method described is reliable and comparable to currently used methods based on genotyping data and susceptibility assays, thus confirming the predictive potential of the non-infectious cell-based method.