Meeting the transfusion needs of a patient with anti-En^a requires an international effort

This extraordinary case showcases the identification of a rare anti-En^a specificity that was assisted by DNA-based red blood cell antigen typing and collaboration between the hospital blood bank in the United States, the home blood center in Qatar, the blood center Immunohematology Reference Laboratory, as well as the American Rare Donor Program (ARDP) and the International Society for Blood Transfusion (ISBT) International Rare Donor Panel. En^a is a high-prevalence antigen, and blood samples from over 200 individuals of the extended family in Qatar were crossmatched against the patient’s plasma with one compatible En(a–) individual identified. The ISBT International Rare Donor Panel identified an additional donor in Canada, resulting in a total of two En(a–) individuals available to donate blood for the patient.