Benign hemoglobinuria following transfusion of accidentally frozen blood

A patient was transfused with a unit of red blood cells that had been frozen accidentally prior to transfusion. Although he had received approximately 60 gm of free hemoglobin intravenously, the patient's only clinical reaction was massive hemoglobinuria. The benign clinical response, in the presence of massive hemoglobinuria, is attributed to the absence of immunologic imcompatibility and, thus, failure to activate vasoactive mediators and disseminated intravascular coagulation. The case illustrates revised concepts of the pathophysiology of acute renal failure associated with hemolytic blood transfusion reactions.