Red blood cell preservation in protein-poor media. 2. Studies of changes in red cell shape during storage.

Red cells stored for up to 35 days have been studied by scanning electron microscopy. Formation of spicules occurred under all storage conditions in CPD and CPD-adenine whole blood, CPD-adenine red cell concentrate, and saline-adenine-glucose red cell concentrate. The number of cells with normal or near normal shape was larger if the blood was stored as a moderately concentrated suspension in saline-adenine-glucose medium or in autologous plasma as compared to the storage as whole blood. The occurrence of echinocytes during storage at +4 degrees C was not correlated to red cell ATP. It was shown that a drastic reduction of ATP leads to an increased formation of both spherocytes and echinocytes. The change of red cell shape during storage at +4 degrees C thus can be due to two processes, one unrelated to ATP and another related to ATP. Why storage as red cell concentrate is superior is not fully understood.