Eight DEA (Dog Erythrocyte Antigen) types are recognized as international standards.[3][4][5] Of these DEA types, DEA 4 and DEA 6 appear on the red blood cells of ~98% of dogs. Dogs with only DEA 4 or DEA 6 can thus serve as blood donors for the majority of the canine population. Any of these DEA types may stimulate an immune response in a recipient of a blood transfusion, but reactions to DEA 1.1+ are the most severe.