The American Rare Donor Program helps locate compatible blood products for patients with rare blood types who have created antibodies that make them incompatible with most or all of the blood products in the hospital blood bank. When these patients with rare blood types need transfusions, they depend on donors with similar rare blood types for blood products. Because blood types are inherited, if a donor with a rare blood type has brothers or sisters, there is a good chance (one in four) that their sibling has the same rare blood type. We encourage siblings of donors with rare types to donate blood so they can be typed to see if they share the same rare type.
