[P50 and stored blood (+4 degrees C and -80 degrees C). In vitro studies].

The authors studied the hemoglobin oxygen affinity (P50) and the 2,3 diphospho-glycerate (2,3-DPG) level in: 33 samples of total stored blood (ACD medium); 14 samples of the same blood after mixing with a solution including inosine, pyruvate, phosphate (I.P.P.); 9 samples of freezed erythrocytes. The increase of the hemoglobin oxygen affinity, associated with a decrease of the 2,3-DPG level appears to be very fast in the samples of ACD stored blood since two hours after sampling, the P50 decrease was of 4 torr. Exposure to the I.P.P. solution (1 H at 37 degrees C), caused the hemoglobin oxygen affinity and the 2,3-DPG concentration to return to their normal values (P50 = 25.4 torr +/- 0.4 torr); 2,3-DPG = 15.6 +/- 0.9 muM.gHb-1). When freezed red blood cells, were defreezed the P50 was found to be 4 torr lower than that of fresh blood and the 2,3-DPG level was also decreased (-4.1 muM.gHb-1). These decreases are probably related to the delay which occurred between blood sampling and freezing.