Can red cell deformability be measured in clinical medicine?

Red cell deformability is a widely accepted term to indicate a property of erythrocytes to adapt their shape to the forces acting in blood circulation. The concept of cell deformability is easy to understand, but it is very hard to evaluate in a numerical way. Several techniques have been proposed but, at present, none can express this biological property with absolute values. Important problems are not yet solvable. The studies in whole blood are influenced by the presence of leucocytes and platelets, and all the procedures which tend to isolate the erythrocytes transform the measurements into technical artifacts. The experience we have had with some new sophysticated and expensive devices has suggested we should not abandon whole blood filtration which, with important but simple technical improvements, remains a method able to value “whole blood filterability’, which is a parameter only partly correlable to “red cell deformability” and not identifiable with it. So, while clinicians need new effected method from biorheologists, the only possible approach to red cell deformability in clinical hemorheology is by means of the interpretation of a pattern of different measurements (blood and plasma viscosity, whole blood filterability, hematocrit, fibrinogen concentration, leucocyte and platelet number and activity).