Stable chronic kidney dialysis patients, currently dialyzing on the main Royal Free hospital dialysis unit will be asked to participate in the study. It is aimed to recruit 15 patients currently dialysing using the Fresenius FX100 dialyzer, who have used Fresenius polysulphone membranes for \> 3 months.
During a mid week dialysis session, dialysis adequacy will be assessed by on line clearance, and samples of both blood and dialysate taken to assess, both clearances and bio-compatibility.
Thereafter patients would be switched to dialyse using the ELISIOTM-H dialyzer, but continue with the same dialysis prescription, and after 3 months, measurements repeated
Assessments Primary Clearances : on-line Kt/V, dual pool Kt/V, phosphate, b2microglobulin, cystatin C Secondary Serum :isoprostane generation complement activation platelet activation - coagulation activation - thrombophilic markers - Other Anticoagulation requirements \& clotted circuits erythropoietin requirements, phosphate control therapy CRP
