"Every cat used for breeding or receiving a transfusion should be blood typed."
- Urs Giger, PD, Dr.med.vet.,MS, FVH; Diplomate, ACVIM and ECVIM
There are three feline blood types: A, B and AB. Cats have naturally occurring antibodies to antigens not on their red cells. Thus cats with type A blood have antibodies to type B antigens, and cats with type B blood have antibodies to type A antigens. Cats with type AB blood have both A and B antigens on the erythrocyte membrane and do not have naturally occurring antibodies to either type A or B blood.
The A type is the most common in cats. The prevalence of type B blood differs by breed. Breeds with a greater than 10% incidence of type B blood include:
Abyssinian 16% Japanese Bobtail 16% Birman 18% Persian 14% British SH 36% Scottish Fold 19% Cornish Rex 33% Somali 18% Devon Rex 41% Sphynx 17%
Cats with type AB blood are rare.
Believe it or not...most cats are not blood typed.
What are the risks of not blood typing cats?
Cats that are transfused, even once, with an incompatible blood type, are at risk for a transfusion reaction. Cats with B erythrocytes exhibit an immediate and catastrophic systemic anaphylactic reaction and a Hemolytic Transfusion Reaction ("HTR") when transfused with type A blood, because of their natural high-titered anti-A antibody Death is extremely likely.
Cats with A erythrocytes and natural low-titered anti-B antibody will exhibit only a mild reaction when transfused with type B blood, but the transfused cells will have a shortened life span. The recipient will develop moderate titers of anti-B antibody that will result in a serious reaction if a subsequent incompatible transfusion is administered.
In general, you don't know a cat needs a transfusion (to treat a blood disorder or trauma) until it's an emergency. Knowing the patient’s blood type can help prevent an iatrogenic emergency.
Serious problems can result from accidental or mismatched mating.
A mating of a type B queen with a type A tom will result in their type A kittens being at risk for neonatal isoerythrolysis (“NI”), commonly known as “fading kitten syndrome”. The maternal naturally occurring, highly titered anti-A antibody occurs in the colostrum where it can be absorbed by the newborn kittens. The absorbed antibody attacks the kittens’ type A erythrocytes. Although the kittens can seem normal at birth, they develop signs after nursing, fade and die within the first days of life. Determining the blood type of the queen and the tom prior to mating, coupled with appropriate genetic counseling, can minimize the risk of NI. Furthermore, immediate blood type determination of the newborn kittens will alert the client to remove the kittens and to begin surrogate nursing where necessary.
The conclusions are clear:
• All cats should be blood typed.
• No cats should be mated before blood typing.
• All kittens resulting from incompatible matings should be blood typed at birth
so that surrogate nursing can be started where necessary and the kittens allowed to thrive.