Case Report Hyperhemolysis Syndrome without Underlying Hematologic Disease

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Hyperhemolysis is characterized by a life-threatening hemolytic transfusion reaction, with hemoglobin (Hb) and hematocrit (Hct) dropping markedly lower than before transfusion. This phenomenon, commonly described in sickle cell disease, is a rare occurrence in patients without hemoglobinopathies. Case Report. A 55-year-old male presented to the hospital after a motorcycle crash and received 10 units of cross-matched blood for active bleeding. The patient was blood group O, with a negative antibody screen. Ten days later, he represented complaining of dyspnea and was found to have a hematocrit of 12%. Th