Delayed hemolytic transfusion reaction associated with Rh antibody anti-f: first reported case

A delayed hemolytic transfusion reaction (DHTR) occurring in a 30-year-old Caucasian man is described. His blood groups were B, CDe/cDE (R1R2, f-) K-, S-s+, Fy (a + b-), and Jk (a + b +). Eight days after receiving two units of packed red blood cells, his urine was strongly positive for hemoglobin; serum-free hemoglobin was 125 mg/dl. Serum contained a clearly reactive Rh antibody of anti-f specificity and a weakly reactive anti-Kell. The DHTR was probably caused by an anti-f alloantibody appearing as an anamnestic response to transfusion of seemingly compatible, but f-positive blood.