[Erythrocyte freezing in the presence of hydroxyethyl starch]

Biochemical properties of erythrocytes frozen in the presence of hydroxyethyl starch (HES) as preserving substance produced in this country were assessed. Erythrocytes were frozen adding HES in 4 different concentrations. The most favourable results were obtained with erythrocytes subjected to the action of HES in 30% and 35% concentrations. The erythrocyte 2,3-DPG level during freezing with 35% HES was within normal limits while it decreased by 10% after defreezing when 30% HES had been used. The ATP concentration in erythrocytes fell by 50% in relation to the initial value. A slight fall of P50 was observed and erythrocyte loss after defreezing did not exceed 10%. The 35% HES solution in a 0.15 mol/l sodium chloride solution was most favourable for freezing erythrocytes in liquid nitrogen. A simple method of preparation of defrozen erythrocytes for transfusion was elaborated.