All high-flux membranes are equal but some high-flux membranes are less equal than others

The progression of renal failure is characterized by the accumulationof a host of compounds [1], which, under normal conditions,are excreted or metabolized by the healthy kidneys. Many ofthese compounds affect several organ systems, resulting in theuraemic syndrome. Once this retention has progressed to disabling or life-threateningcomplications, quality of life and survival can only be maintainedby removing retention products by dialysis or transplantation.Over time, it became clear that many of the disabling retentionsolutes (toxins) are difficult to remove by standard dialysis,as they are either protein bound and/or characterized by a highmolecular weight (middle molecules) [2,3]. Removal of such compounds by currently available dialysis strategiescan be achieved by increasing dialyzer pore size, i.e. applyinghigh-flux membranes, alone or in combination with convection.Mainly based on secondary analyses of