On how macromolecules reduce hemoglobin loss in hypotonic hemolysis

When human red cells are hemolysed in hypotonic solutions containing macromolecules, the hemoglobin loss from the individual cells is reduced although the number of cells hemolysed is not affected. The evidence strongly suggests this is a colloid osmotic effect but an additional condition is also necessary if hemoglobin is to be retained. The cell must reseal, at least to hemoglobin and macromolecules. There is some evidence which points to the role of the macromolecule in this process. Further, at least in the case of dextrans, a minimal size of about 2000 daltons is required for suppression of hemoglobin liberation and it is suggested that this limit may be set by the diffusion coefficient.