ABSTRACT
Dialysis describes the diffusion of solute across a semi-permeable membrane and down a concentration gradient. Filtration is the movement of solute by convection across a semipermeable membrane. Dialysis is particularly efficient for small molecules such as K+, Na+ and urea. Dialysis can be undertaken by using an artificial membrane or the peritoneum. It can be performed continuously or intermittently. The size of the molecules removed by filtration will depend on the cut-off point (size of the holes) of the artificial membrane. Membranes designed for dialysis or filtration are most commonly made of polyacrylynitrile. This is a biocompatible material and is unlikely to cause significant complement activation.
