Blood Types in Pets

Cats, with only Two Blood Types have Good Success with Kidney Transplants


One of my students asked me if animals of the same species have different blood types like humans. For example: if you needed to give a cat a blood transfusion would you need to find another cat with the same type of blood (for example type A or B etc.) for the transfusion to be successful?


Dr. Nichol:

Yes, other species have blood types too. Dogs are known to have eight; cats have two. Determining the specific blood type is only important if a pet has had a previous transfusion.


When blood is given, the immune system recognizes right away if the red blood cell proteins of the donor blood are similar (the same blood type) to those of the recipient. If the donor blood is of a different type, a first transfusion is likely to go fine anyway because the recipient’s immune system has never met those foreign blood proteins and has never made antibodies against them. A second incompatible transfusion would be a very different story because the recipient now has antibodies that will break red blood cells of the wrong type. Only the correct type would be safe and effective for a system that was once fooled.


Cats, with only two blood types, are luckier than dogs-and not just with transfusions. Kidney transplants usually work well in cats because any healthy cat of the same blood type can make a fine donor. Only minor anti-rejection drugs are needed. Are cats better than dogs? I can’t say. Peter Rabbit and Raoul read my column every week and I can’t bear the thought of seeing this page in the litter pan.