Both dogs and cats have antigens in their red cell membranes that determine blood type. The cat system is the simplest, with cats either having type A, B, or AB blood. Type A cats may receive type A, B, or AB blood with little chance for transfusion reaction. Virtually all domestic shorthair and Siamese cats in the United States are of type A.
Cats with type B blood who receive any amount of type A blood experience a rapid and life-threatening transfusion reaction, usually resulting in death. Breeds with a high incidence of type B antigen are Abyssinian, Persian, Himalayan, British Shorthair, and Rex cats.
In the canine population, 8 major dog erythrocyte antigens (DEA) have been identified. Two dog erythrocyte antigens, DEA 1.1 and 1.2, produce major transfusion reactions when type DEA 1.1 or 1.2 blood is administered to dogs with antibodies to DEA 1.1 or 1.2. About 60% of the dog population have the blood types DEA 1.1 or 1.2. Dogs with the DEA 7 blood type whose blood is transfused into an incompatible dog (one with DEA 7 antibody) may experience a minor transfusion reaction.
There are no canine breed predilections for any of the blood types. The ideal or ?universal? canine blood donor is negative for DEA 1.1, 1.2, and 7 blood types.
The most effective way to determine blood compatibility prior to a transfusion is to crossmatch donor and recipient blood. Crossmatching takes about an hour to perform and requires no special equipment. This procedure is reviewed on page 554 in the text Veterinary Emergency Medicine and Critical Care Medicine (Murtaugh and Kaplan, eds. Mosby Yearbook; St. Louis, 1992).
If crossmatching cannot be done, the safest way to minimize transfusion reactions is to administer blood of known donor type to patients. Blood of potential cat and dog donors can be typed for $35 per submitted sample through Dr. Robert Bull?s Immunohematology and Serology Laboratory, B228 Life Sciences, Michigan State University, East Lansing, MI 48824 (517-353-4616).
All blood transfusions given to canine patients at Michigan Veterinary Specialists are from universal donors. So far all of our cat donors are type A. If you know of any type B cats, please call Dr. Robert Fulton (810-354-6660).
TRANSFUSION FACTS TO REMEMBER
The first transfusion a dog receives, even from a dog with a blood type different from that of the recipient, is unlikely to cause a transfusion reaction because dogs must be sensitized to DEA via transfusion.
Once a dog receives a transfusion of an incompatible blood type, it will develop antibodies to the incompatible DEA in approximately 7 days. Transfusion of incompatible blood once antibodies have formed will result in transfusion reactions.
Cats have naturally occurring (pretransfusion) alloantibodies to erythrocyte antigens and thus may have reactions to their first blood transfusion.
Robert Fulton, D.V.M.
MVS Emergency Medicine Service