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All About Blood Transfusions in Dogs and Cats

Animal blood banks are desperate for donors — and your pet might make a great candidate. Here’s what you need to know.

blood transfusions in dogs
Blood transfusions in dogs may be necessary when the dog’s red blood cell count is too low. Photo: groesswang

What do you know about blood transfusions in dogs and cats?

You probably have an idea they are possible, but you’re not sure of the how, why and where.

It’s time to raise awareness of blood transfusion medicine for cats and dogs. After all, one day it could be your pet’s life on the line.


Blood Transfusions in Dogs and Cats

So, why are blood transfusions given?

If your mind is like mine, it jumps straight to trauma, like a pet getting hit by a car.

But there are plenty of other ways a cat or dog can lose blood. The most common reason I use blood is for dogs with tumors on the spleen who are about to undergo high-risk surgery to remove the diseased organ.

However, there are other reasons, such as pets with anemia due to autoimmune disease (they destroy their own blood cells) or dogs who have eaten coins or metallic objects containing zinc (which damages red blood cells).

Veterinarians make the decision about whether or not to give blood based on the pet’s packed cell volume (PCV), a measure of how many red blood cells are in the serum. If the numbers are too low, a blood transfusion may be necessary.

Cat and Dog Blood Types

Every red blood cell has markers (or antigens) that sit on a cell’s surface like little spikes. These different markers determine an animal’s blood type.


Dogs are typed according to the dog erythrocyte antigen (DEA) system. This is where it gets a bit complicated — there are 6 blood types (DEA 1.1, 1.2, 3, 4, 5 and 7), of which DEA 1.1 dominates the scene and is the most significant.


A DEA 1.1 negative dog who is given DEA 1.1 blood will become very sick. However, DEA 1.1 negative dogs can be considered “universal donors,” meaning their blood is likely to be safe to give to dogs who haven’t been typed.

In the times before vets had access to test kits in the clinic, it was considered fine (in an emergency) to give a dog a single blood transfusion because the risk of a rejection reaction was low and, if it happened, drugs could save the day.

Now, with test kits available, it is standard practice to type both donor and recipient to match them. Most clinics type the recipient and then phone a blood bank for a compatible sample.

blood transfusions in pets
Your cat or dog can donate to a blood bank for other pets in need. Photo: Daga_Roszkowska


The 4 cat blood types are A, B, AB and Mik.

Type A is the most common, with around 99% of cats in the United States falling into this group.

Blood transfusions in cats are a lot more problematic than they are for dogs — there is a more even spread of blood types (rather than the domination of DEA 1.1), and rejection reactions are much more likely.

In addition, rejection reactions in cats are more sudden and violent than in dogs and can be rapidly fatal. This is why sick cats in need of blood cause vets more headaches than the equivalent dog, and it’s why cross-matching is essential.

How Your Pet Can Become a Blood Donor

Blood banks are desperate for donors, and donation is something everyone should consider.

However, the donor pet must meet strict criteria. These are largely to do with screening for infectious diseases that could be passed on and to check that the pet is healthy enough to cope with giving blood.

Factors such as temperament also come into play. It takes around 30 minutes to draw the sample, so stressed or aggressive individuals must be sedated — which isn’t ideal for anyone.

Learn a little more about blood transfusions in dogs in this video:

Ideal Dog Blood Donor

  • Healthy
  • Screened as free from infectious disease
  • Medium or large breed weighing over 55 pounds
  • Vaccinated (but not in the past 2 weeks)
  • Friendly
  • 5–8 years old

Ideal Cat Blood Donor

  • Healthy
  • Screened as free from infectious disease
  • Weighs at least around 10 pounds
  • Young or middle-aged

Local anesthetic cream numbs the skin while the sample is collected, and good-natured dogs usually lie or sit still for the duration with the inducement of treats.

Final Thoughts on Blood Transfusions in Dogs and Cats

Blood transfusions save lives.

If your pet wants to help save the lives of other furry friends, speak with the staff at your local veterinary clinic. They can collect the blood and forward it to the bank or put you in touch with the bank directly.

vet-cross60pThis pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Aug. 24, 2019.

If you have questions or concerns, call your vet, who is best equipped to ensure the health and well-being of your pet. This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. See additional information.