Abstract
On-line hemodiafiltration (ol-HDF) may improve clinical outcome in ESRD. The supposed mechanism is the improved clearance of uremic toxins by convective transport which is added to the diffusion transport. However, recent marked improvement in the performance of dialyzers has allowed higher removal rate of middle to large solutes by diffusion. It is inaccurate to define substances with a higher molecular weight such as uremic toxins. In addition, new methods should be developed for the removal of protein-bound substances. A technical fee for on-line HDF was newly established on the revision of the reimbursement for medical services Japan in 2012 and clearly separated from off-line HDF. As a facility requirement, the calculation of ‘addition for maintaining dialysis fluid water quality' was added. Evidence for the clinical effects of ol-HDF have been reported mainly in Europe but is still inaccurate. To confirm the effectiveness of ol-HDF, randomized comparative trials on hemodialysis using super high-flux dialyzers and ol-HDF with same performance hemodiafilter are necessary.