The proper use of previously frozen red blood cells for transfusion.

T HE SINGLE incontrovertible indication for transfusion of frozen-stored red blood cells (FSR BC) is: to provide readily available rare donor blood for patients allosensitized to high-frequency donor antigens. Other alleged indications have not been adequately documented. It is useful to examine the background for so restrictive a definition. In 1950, it was first demonstrated that human red blood cells (RBC) could be stored frozen for prolonged periods, thawed, washed free of cryopreservative, and transfused with normal in vivo survival of 85%.-90% of the recovered cells.’ In the first blush of excitement at achieving the science-fiction goal of suspended animation, it seemed possible that frozen storage of RBC might be the panacea for most of the problems that beset the transfusion field. In particular, it should be possible to stockpile blood in large quantities and for prolonged periods, eliminating the problem of seasonal shortages and providing an important resource to meet unexpected major local or national catastrophes; another blessing would be the establishment of enduring supplies of rare donor bloods so that they could be made available in sufficient numbers whenever needed. During the succeeding 20-25 yr, RBC freezing technology was refined, 800 air refrigerators and 1400 gas phase liquid nitrogen storage containers were mass produced, mechanical cell washers for cryopreservative removal were developed, FDA standards were issued, and the number of units of FS-RBC escalated to more than 100,000 annually. It appeared that the 1950 dream was coming true! During this developmental period, increasing numbers of virtues were ascribed to FS-RBC when compared to conventional whole blood and packed RBC: ( I ) they could be transfused uneventfully to patients experiencing frequently recurring febrile transfusion reactions secondary to sensitization to donor leukocytes and platelets.2 (2) they were well tolerated by the rare patients who