Permeability of membrane to potassium in hypochromic red cells with different specific density

In hypochromic anaemias (heterozygous beta-thalassaemia and iron deficiency anaemia) ligher red cells lose more K+ than heavier ones, following incubation at 37 degrees C for 24 h. Both in the light and heavy fractions two subpopulations of cells with different permeability to K+ can be separated by a new centrifugation after incubation. On the basis of the results, a relationship between K+ permeability and probability of survival in hypochromic cells is suggested.