Distributions of rheological parameters in populations of human erythrocytes

We have previously proposed the osmofiltration method based on a modified Hanss hemorheometer to analyze distributions of erythrocytes in their ability to pass through membrane filters with 3 microns pores. Upon decrease in medium osmolality (u) the erythrocyte volume increases. When cell volume becomes V = Vcr at u = ucr, such cell loses its ability to pass through a 3 microns pore. The flow rate of erythrocyte suspension containing cells with different ucr through a filter gradually decreases with decreasing medium osmolality. 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 filter. 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 erythrocytes in ucr. Here, we propose a simplified version of this method, which allows screening of the erythrocytes in heterogeneous suspensions for the distribution in ucr by measuring omega for only two hematocrit values, 0.1% and 1%. Applications of the proposed method are exemplified by analysing the erythrocyte populations of healthy donors, of patients with microspherocytosis, hemochromatosis and normal erythrocyte populations in an acidic environment.