A technique to detect reduced mechanical stability of red cell membranes: relevance to elliptocytic disorders.

A method has been developed for determining the relative tendency of red cell membranes to fragment under shear stress. For these measurements. resealed ghosts were subjected to constant, high fluid shear stress in an ektacytometer. The deformability signal. which this instrument provides. progressively declined as the deformable cells were transformed into less deformable, more spherical cell fragments. The deformability signal for normal ghost preparations decayed over a narrowly defined time period; this decay was accompanied by the production of cell fragments. as shown by microscopic examination and analysis of particle volume distribution. The method was used to study cells from patients with various hemolytic disorders. Membrane preparations from patients with various types of nonhemolytic congenital elliptocytoses showed a reduction in the time required for fragmentation to about half the normal value. Membrane preparations from patients with