ABO incompatible blood transfusion.

Four cases of ABO incompatible blood transfusion are presented which occurred over a 3-year period and resulted in marked clinical variation. In each instance the error leading to the transfusion resulted from the incorrect identification of either the patient, the crossmatch sample or the donations. These cases not only highlight the problems in the clinical recognition of ABO incompatibility but indicate a need to shift emphasis from refining crossmatch methodology to the strict following of standard established protocols for transfusion. It is of paramount importance to guarantee the failsafe identification of blood specimens, donations and recipient to minimize the possibility of accidents due to human error.