At this time, production of antisera for identifying DEA 3 is not available. The probability is only about 5% that a dog would be positive for DEA 3. In the event that DEA 3 is present, a delayed removal of red cells from circulation after transfusion may result (this as opposed to the acute hemolytic reaction caused by DEA 1 antigen/antibody interactions which places a dog at immediate risk.) To avoid the unlikely reaction from an incompatible DEA 3 transfusion, a cross match test should always be performed prior to each transfusion. (Click for Hematology Supplies) This should always be done as a matter of routine regardless of blood type as a cross match will identify any rare reactions blood typing alone does not identify.