Age dependent changes in osmotic hemolysis of human erythrocytes.

The osmotic fragility curve and the rate of hemolysis in hypotonic solution were investigated for individuals of different age. It was found that in older individuals the erythrocyte is more fragile with a broader and more asymmetric distribution of fragilities, while the rate of hemolysis is significantly slower for older individuals. The increase in fragility with age can be attributed to the increase in cellular volume, while the decrease in rate of hemolysis with age can be attributed to change in the properties of the erythrocyte membrane. All the changes with respect to individual age cannot be explained by a change in the distribution of cellular ages, and some changes in the formation of erythrocytes and/or the plasma environment of the erythrocyte must take place.