Cat Blood Types Explained

During a medical emergency, it may be necessary to give your cat blood in a transfusion. If this is the case, it is important to be aware of your cat’s blood type, as well as the general breakdown of feline blood types and their cross-compatibility. In addition to these situations, feline blood types play an important role in cat breeding, and breeding along improper blood type combinations may result in a poisonous and fatal situation for kittens before and during the labor process. Continue reading for additional information about feline blood types and their mixing.

The Three Feline Blood Types

All cats have one of three primary blood types. These are classified as A, B and AB. Among these, type A is far and away the most common. In fact, roughly 99% of all domesticated short hair cats in the world have type A blood. There is some variation in this percentage according to the breed of cat and the location, but in all short hair breeds type A is predominant.

Type B blood is found primarily in purebred cat breeds. The breeds with the highest incidence of type B blood are British Shorthair, Himalayan, Persian, Devon Rex, Cornish Rex and Sphinx breeds. Type B blood has a natural antibody against type A blood, and type A blood has an antibody against type B blood, meaning that these blood types cannot be successfully mixed in a transfusion.

The third type of blood occurring in cats is type AB. AB blood is exceedingly rare, but it has the benefit of not containing antibodies against either type A or type B blood. As a result, AB blood cats are universal receivers, and may receive blood transfusions from all other cats. There is no universal donor blood type in cats.

The Dangers of Improper Mixing

Mixing or transfusing blood improperly is often fatal in cats. Even a very small quantity of type A blood in a type B cat, or type B blood in a type A cat as well, may prove fatal to that cat. 

One other very important consideration to keep in mind regarding feline blood types is the dangers of breeding cats with incompatible bloods. Neonatal isoerythrolysis is a fatal condition in which a mother’s milk destroys a kitten’s red blood cells, and it is caused by incompatibility between mother and kitten blood types. 

A mother with type B blood who gives birth to a kitten with type A blood may cause isoerythrolysis in those kittens. This situation arises when a type A male is bred to a type B female. Type A blood is dominant, so the situation does not occur when a type B male is bred to a type A female.

Because of the risk of this serious condition, it is crucial that you have the mother and father tested for blood type before pregnancy occurs, and especially before labor. If the mother is type B and the father is type A, consult with a veterinarian for alternative nursing methods and other preventative measures. 

With the proper prevention and knowledge, you can safely and confidently breed cats and manage your pet’s blood transfusions.