Just like people, animals can benefit from blood transfusions when they become ill or are injured. There are many different reasons why an animal may need a blood transfusion. For example, if they have been hit by a car or ingested rodent poison a blood transfusion could be a matter of life or death.

Blood is species specific-dogs can receive only dog blood and cats can receive only cat blood. In addition, dogs and cats have blood types just as humans have blood types. Cats have A, B, and AB groups with specific factors within these groups that further differentiate them. Dogs have eleven different blood groups; the most important one is the A1/A2 system. Dogs that are A negative are considered universal donors. Cats do not have a universal donor; therefore, it is especially important that donor and recipient are cross-matched.