Distributions of rheological parameters in populations of human erythrocytes

We have previously proposed the osmofiltration method based on a modified H anss hemorheometer to analyze distributions of erythrocytes in their abilit y to pass through membrane filters with 3 mu m pores. Upon decrease in medi um osmolality (u) the erythrocyte volume increases. When cell volume become s V = V-cr at u. = u(cr), such cell loses its ability to pass through a 3 m u m pore. The flow rate of erythrocyte suspension containing cells with dif ferent u(cr) through a filter gradually decreases with decreasing medium os molality. This rate becomes zero at some u = Omega, when the number of non- filterable cells in the applied sample approaches the number of pores in fi lter. Experimental determination of the dependencies of the filtration rate on medium osmolality for various hematocrit values allows to obtain Omega for each hematocrit and, thereby, to assess the distribution of erythrocyte s in u,,. Here, we propose a simplified version of this method, which allow s screening of the erythrocytes in heterogeneous suspensions for the distri bution in u(cr) by measuring Omega for only two hematocrit values, 0.1% and 1%. Applications of the proposed method are exemplified by analysing the e rythrocyte populations of healthy donors, of patients with microspherocytos is, hemochromatosis and normal erythrocyte populations in an acidic environ ment.