Transfusion management in the presence of anti-k (Cellano) alloantibody: insights from two case reports

Anti-k (Cellano, KEL2) is an uncommon but clinically significant Kell-system alloantibody because the k antigen is highly prevalent in most populations, making compatible red cell units difficult to obtain. We report two cases in which pretransfusion testing showed a positive antibody screen with strong (3+ to 4 +) reactivity in the antiglobulin (AHG/IAT) phase across all three screening cells, with no reactivity at room temperature and a negative autocontrol, suggesting a high-prevalence red cell antigen. The specimen was referred to an immunohematology reference laboratory, where anti-k was identified. The patient was advised to receive ABO/Rh(D)-compatible, k-negative, leukoreduced red blood cells that are crossmatch-compatible by AHG, with coordination through reference laboratory/rare donor resources to prevent transfusion delays and avoid hemolytic transfusion reactions. These cases underscore the importance of recognizing AHG-phase pan-reactivity with a negative autocontrol as a clue to antibodies against high-frequency antigens and highlight the need for early referral and proactive blood procurement in surgical patients.