Katrine Kielsen, Bibi Fatima Syed Shah Scharff, Anne Todsen Hansen, Line Malmer Madsen, NielsErikstrup Clausen, Klaus Rieneck, Morten Hanefeld Dziegiel*
Hemolytic Transfusion Reactions (HTR) caused by antibodies against the high-prevalence Coa antigen has rarely been reported, and Coa-negative Red Blood Cells (RBC) units are rare.
A 74-year-old woman was admitted with gastro-intestinal bleeding and sepsis. She developed an alloantibody of unknown specificity after her first transfusion. After a third, urgent transfusion with a Coa incompatible RBC unit, she reacted with dyspnea, hypertension, cerebral impairment and ultimately cardiac arrest. Hemolysis was demonstrated, an anti-Coa was detected in her serum, and post transfusion investigations identified the implicated RBC unit as Co (a+b-). In the following weeks, the patient’s persistent need for RBC transfusions was met by fresh Coa-negative blood enabled by our recently implemented routine genotyping of blood donors. Genotyping of the patient’s blood group antigens was an important diagnostic tool in the identification of the antibody, and large-scale genotyping of blood donors proved to be of great value to procure Coa negative blood.