Safety measures to prevent ABO-incompatible red blood cell (RBC) transfusions are in place throughout the entire process from blood donation to the recipients’ bedsides, though practices vary between countries and facilities. Preventive safety measures have reduced ABO-incompatible transfusions to less than one in 100,000 transfusions. Researchers in Europe explored the causes and frequencies of ABO-incompatible RBC transfusions in France, Germany,…