Adsorption of plasma proteins onto the membrane surface during the hemodialysis session represents a key feature of membranes used for chronic dialysis therapy. A newarticle published in Proteomics originally described how by using proteomic technologies the adsorptive properties of two membranes made from the same biomaterial may have different flux characteristics low flux and high flux . In this study a total of 497 differentially expressed proteins were identified in eluates obtained after in vivo hemodialysis 320 proteins concentrated more in low flux membrane predominantly proteins with molecular weight 30 kDa 60 kDa and 177 in high flux most represented by proteins with molecular weight 10 kDa 15 kDa . Use of bioinformatics tools revealed the involvement of adsorbed proteins in important biological pathways such as the coagulation cascade and the complement system again with some differences between the two membranes. The findings of this study suggested that flux characteristics of a biomaterial used for hemodialysis membrane strongly influence its adsorptive properties and that proteomic application may provide information relevant to renal replacement therapy.