The recipient must not have any evidence of clinically significant antibodies, presently or in the past. At least two concordant results of ABO and RhD typing must be on record, including one from the current sample. Additional laboratory information system requirements VX 809 must also be met. When electronic crossmatching is performed neither an immediate spin nor antiglobulin phase crossmatch between recipient plasma and donor red cells is required. Electronic crossmatch has cost–benefits and is safe for most patients. However, it is known that potentially clinically significant antibodies, including antibodies to low incidence antigens may be missed by electronic crossmatch [6].

We report here a case of a clinically significant acute extravascular hemolytic Gamma-secretase inhibitor transfusion reaction mediated by previously unrecognized (and undetected) anti-Kpa antibody in a patient who met all criteria for electronic crossmatch, resulting in the transfusion of an incompatible red cell unit. A 64 year old clinically obese female with diabetes

and previous history of myocardial infarction was admitted for urgent repair of a hiatal hernia. The patient had two previous pregnancies. The patient had remote history of transfusion in the 1980s through which she acquired hepatitis C. The patient had a more recent history of red cell transfusion with one unit of red cells transfused after gastrointestinal bleeding 5 years earlier at which time no antibodies were identified. The patient was blood group O, RhD positive. At the time of current presentation, the antibody screen was negative. The hemoglobin was 82 g/L pre-transfusion. One unit of group O, RhD positive, leukoreduced packed red blood cell (PRBC) unit was issued to the patient after electronic crossmatch indicated compatibility. During the transfusion, the patient experienced an elevation in temperature, from 37.9 °C pre-transfusion to 39.5 °C during transfusion, accompanied by chills/rigors, and soon followed by shortness

of breath. The transfusion was permanently discontinued. At this point the patient had received about 200 mL of PRBCs. Immediately after the transfusion the hemoglobin was 90 g/L. The patient was Ribonucleotide reductase given supplemental oxygen, bronchodilator (salbutamol) and bilevel positive airway pressure (BPAP) ventilatory support for a few hours. The patient’s signs and symptoms resolved within a few hours with no additional intervention. Patient blood cultures and cultures of the remainder of the PRBC unit were negative. Transient elevation of the total bilirubin and lactate dehydrogenase was noted (Fig. 1). Transient elevation of troponin I was observed following the incompatible red cell transfusion, peaking just before the surgery (Fig. 2). EKG performed before the incompatible red cell transfusion showed old anterior myocardial infarct.