Dialyzers, used in HDF, have high hydraulic permeability. They make i t easy to collect extra sodium from body water especially in high sodium concentration therapy. We evaluated the HDF therapy employing high sodium concentration in the substitute fluid or dialysate in this report. The storage of dialysate drainage taught us total amounts of solute (or sodium) removal M (or M Na+). Then we knew that M has no relationship to sodium concentration but dialyzer clearance. And we can hardly know sodium concentration exactly, so it is quite difficult to calculate M Na+). It means that the evaluation of high sodium concentration therapy by M Na+ is impossible. We concluded that every patient has his own fitted sodium concentration in each therapy.
