Storage of Human Red Blood Cells II. The effect of pH and of the addition of adenine

Blood was stored for different periods of time in three solutions 1) ACD solution 2) a less acidic medium and 3) a neutral solution containing citrate and phosphate buffer. At the beginning of the storage period the pH of the blood ranged from 6.8 (ACD) up to 7.4 (neutral solution). Furthermore the effect of the addition of adenine to each of these three solutions was tested. In some experiments storage of blood with final hematocrit values of about 66% instead of the usual about 40% was also investigated. With the two more neutral media hemolysis and glycolysis were more pronounced than in the acidic medium. Addition of adenine to the three solutions decreased hemolysis and increased glycolysis but its effect was much more pronounced in the two more neutral media. It was possible to maintain the concentration of 2,3‐diphosphoglycerate in the erythrocytes if the cells were kept in a neutral solution, although this method gave a more rapid drop in the ATP level. In the more acid solutions the concentration of ATP remained higher, but the 2,3‐diphosphoglycerate rapidly disappeared. No major differences were observed between blood preserved in ACD solution with hematocrit of about 66% and the usual hematocrit of about 40%.