An unusual report of anti‑N antibody presenting as ABO discrepancy in an old female patient in Palestine

The MNS is a highly complex immune blood group system which is almost equal to Rh in size and complexity. Anti‑N antibody is naturally occurring in general, cold reactive IgM or IgG saline agglutinin and relatively rare when compared with anti‑M. The immune type anti‑N is seldom encountered. Anti‑N antibody is not clinically significant unless it reacts at 37°C. Clinically significant anti‑N antibody is reactive at 37°C or in the anti‑human globulin phase, which may cause delayed hemolytic transfusion reactions or hemolytic disease of newborn. Here, we report a rare case presented as blood group discrepancy of a naturally occurring anti‑N that reacts at 37°C.