Blood Transfusion in Animals
By Dr Florence Chan
There are many situations where animals require urgent blood transfusion. Road
accident causing external and internal bleeding, high-rise syndrome in cats (ie falling
from high-rise apartment windows), rat-bait poisoning, profound anaemia caused by
tick fever or autoimmune disease, tumour in the spleen and/or liver or stomach ulcers
causing massive internal bleeding etc. It might surprise a few people that our dogs
and cats can receive blood transfusion, and that often saves lives.
Dogs and cats, just like human, have different blood types. Dogs have many different
blood types (more than 10), making it difficult to categorize individual dog’s blood
group with commercial test kits. The good
news is, however, dogs do not have natural
antibodies against other blood types, meaning
that we don’t have to match the blood type
between donor dog and recipient dog in the
first blood transfusion. However subsequent
transfusions might invoke serious reactions
and so it is recommended to perform a crossmatch between donor and recipient before any
subsequent blood transfusion.
The situation in cats is a little bit similar to human. Cats have the following blood
type: A, B and AB. Majority of cats have type A blood, while certain pedigrees e.g.
British Shorthaired and Exotics, appear to have a higher prevalence of type B cats.
Cats have natural-occurring antibodies against other
blood groups and can develop potentially severe
allergic reactions when the wrong blood type is being
transfused. The situation is the worst and can be
fatal when a type B cat is given type A blood. As a
result, it is always recommended to identify the
blood type of both the donor cats, and the recipient
cats and to always perform a cross-match before any
blood transfusion to be certain of their compatibility.
There is currently no commercial blood bank for our dogs and cats in
Hong Kong, so where do we find blood when we need it?
Some clinics purchase blood products from overseas canine
commercial blood banks. Both packed red blood cells and fresh
frozen plasma are available commercially, being collected from
universal donors and then processed to the desired products. The
advantages of such products are immediate availability (when in
stock) and quality assurance (standardized donor – disease-free). The
disadvantages of these are the high cost, limited shelf-life, shipment
from overseas not always available, and the lack of platelets and other
blood proteins that would be beneficial in some coagulopathies. Also,
currently there is no feline blood product available for purchase.
Another option is to find donor animals to come in for blood donation, then
immediately transfuse the donated blood to our patients. Most clinics rely on their
staff’s pets, or goodhearted clients to bring their animals in for donation when blood is
needed for another patient. Most owners are actually quite happy for their pets to
“fulfill their duties towards their own kind” and be a hero when approached!
What makes the perfect donor animal?
Young, healthy and friendly
> 25kgs (dogs) and > 4kgs (cats)
Up to date with vaccination, heartworm prevention and deworming
Never received a blood transfusion before
Never been pregnant (females only)
Free of any blood-borne disease (e.g. tick fever)
During the blood collection process sedation is sometimes required. The process
usually doesn’t take more than 1/2 hour and we usually allow the donor animal to rest
for a while before sending them home. There should not be any detrimental effect to
our donors after the donation.
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