Pet Columns, Office of Public Engagement, College of Veterinary Medicine at the University of Illinois at Urbana-Champaign

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Blood Transfusions for Pets


Pet Column for the week of June 29, 1998


Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
By Sarah Probst
Information Specialist

"A number of animals who come in for emergency care at veterinary clinics wouldn't survive
surgery or trauma unless blood was made available for them," says Kristi Stasi, veterinary
technician at the University of Illinois College of Veterinary Medicine Teaching Hospital.
"The process of collecting and transfusing blood is very similar in veterinary and human
medicine."

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.

Multiple transfusions can also be a problem. Even though the donor and recipient may be
compatible originally, the recipient's immune system may build up a sensitivity to a specific
donor. "Thus, every time you transfuse, you need to cross-match to make sure that your
donor and recipient are compatible," explains Stasi.

There are two types of cross-matching tests: major and minor cross-matching. "For major
cross-matches, red cells from the donor are mixed with serum from the recipient. We
observe to see if there is a reaction; the recipient may attack donor cells and not accept
them. If you have a major cross-match incompatibility, unless you are desperate, you
shouldn't do a transfusion," explains Stasi. In a minor cross-match, the recipient's red cells
are compared with the donor's serum. Usually, in minor incompatibilities, parts of the
donor's blood can be given to the recipient but not the blood in its entirety.

The different blood components-red cells, plasma, and platelets-can be separated if need
be. "Red cells are given to a patient that may be anemic due to trauma or due to a treatable
disease. Plasma is used to build up blood volume in situations when the animal is not making
enough or is losing too much protein. Platelet-rich plasma is for those patients whose
platelets are depleted or dysfunctional," says Stasi.

As with human blood donors, animal donors are tested to make sure blood values are high
enough and no infectious disease is present before blood is drawn. Donors must meet
weight requirements-10 pounds for cats and 50 pounds for dogs. Fluid is replaced after
blood is drawn, and the body compensates by producing new red blood cells. Also similar
to human donors, there must be a waiting period of at least two months before blood is
collected again.

Private veterinarians sometimes use their pet dogs or cats as blood donors when
emergencies arise. The University of Illinois Veterinary Medicine Teaching Hospital relies
on one of a small number of canine blood banks in the United States to meet the needs of
most of its patients.

For further information about pet health, contact your local veterinarian.