Haematological and general factors influencing sieving. A general and prospective review.

From the clinical point of view the factors influencing sieving of RC are numerous and act together in whole blood. Furthermore their in vivo effect is difficult to appreciate for a given vessel. The technological factors can be overcome but only for a given in vitro shear stress. The extrinsic factors are plasmatic or sub-membranial. Some of them are pathological, but others are merely variations of normal parameters. Some 'statistical' factors have been found but without any idea of their relationship to the RC. The intrinsic factors, which are essentially metabolic can be studied after careful washing of the RC. Thus it appears that the management of blood, including washing is of great importance. Finally the biochemical research of the intrinsic, and those we refer to as sub-membranial factors, especially in diabetes and thrombosis, are the more important route of research in this field of filtration of RC.