Hemolytic transfusion reaction following transfusion of frozen and washed autologous red cells A case of hemolytic transfusion reaction, accompanied by hypotension and followed by transient renal failure, occurred after the transfusion of 1 unit of previously frozen autologous red cells. Subsequent investigation revealed the probable cause of the hemolysis to be inadequate deglycerolization of the unit. The cause of the associated symptoms is unknown. Possibilities include nephrotoxic effects of hemoglobin or stroma, toxic effects of glycerol, or release of vasoactive or thrombogenic substances from lysed red cells. This case of a hemolytic reaction adds to the known risks of autologous transfusion. 