Table 1.

Approximate alloimmunization rates to non-ABO blood group antigens reported in various patient populations

Population	Most common antibody specificity	Approximate alloimmunization rate	Exposure	Other notes/comments
General transfused population [6, 7, 8, 9, 10]	K, E	<1–4%	RBC transfusion	primarily retrospective studies; alloimmunization rates of 8–10% reported in prospective transfusion studies
Rh-negative healthy volunteers [21, 22]	D	83–93%	intravenous RBC infusion	anti-E, anti-C and/or anti-G also detected in some volunteers
Young children [23, 24, 25, 26, 27, 28]	K, E	vanishingly rare	RBC transfusion	may be associated with severe infection or treatment with infliximab.
Hospitalized, non-oncology patients [14, 15]	primarily C, E, K	20–30%	RBC transfusion	military combat veterans may be at increased risk compared to civilians
SCD [29, 30, 32, 33]	primarily C, E, K	Up to 47%	RBC transfusion	several guidelines recommend the provision of C, E and K matched RBCs for transfusion in this population
Myelodysplastic syndromes [40, 41, 42, 43]	Rh and K	Up to 58.6%	RBC transfusion	most studies utilized FAB criteria for diagnosis of MDS
Thalassemias [34, 35, 36, 37]	Rh and K	Up to 37%	RBC transfusion
Pregnancy (prior to RhIg) [86]	D	7.2%	fetal-maternal hemorrhage	substantially reduced by the introduction of Rh(D) immune globulin
AIDS [87]	–	none reported	RBC transfusion	further study needed

AABB = American Association of Blood Banks; FAB = French American British classification of hematologic diseases

MDS = myelodysplastic syndromes; SCD = sickle cell disease.