Automated Differential Agglutination Technic to Measure Red Cell Survival

The survival after transfusion of ACD‐stored and of previously frozen red cells was measured by means of an automated differential agglutination technic which permitted simultaneous quantitation in the same recipient of red cells preserved by two different methods. The previously frozen red cells were preserved with a high concentration of glycerol, using the slow freeze‐thaw technic, and were recovered by agglomeration. Severely damaged red cells in both ACD‐stored and previously frozen blood were removed during the transfusion, and less deteriorated red cells were removed at an accelerated rate, usually over the initial 24‐hour posttransfusion period. The mean loss in vitro of red cells related to the freezing process was 28 per cent. The transfused previously frozen blood contained nonviable red cells in amounts comparable to ACD blood which had been stored at 4 C for longer than two weeks, Red cells remaining in circulation 24 hours after transfusion were usually removed at a slower constant rate, and the mean life spans of viable cells from either ACD‐stored or previously frozen blood were similar.