A simple method for measuring erythrocyte deformability.

To pass through the microcirculation red blood cells (RBCs) need to undergo considerable deformation. The increased rigidity of older cells is probably the main cause of their selective trapping by the spleen; and indirect evidence suggests that impaired deformability may be a critical factor in causing diminished peripheral blood flow (Chien et al, 1967; Schmid-Schonbein et al, 1969; Weed, 1970). Several techniques have recently been developed to measure this property of the RBC, but so far none has achieved wide acceptance. The method described here is comparatively simple and has given reproducible results. It is a modification of the technique evolved by Schmid-Sch6nbein and