Xenotransfusion describes transfusion of blood between different species and is most reported in veterinary medicine between dogs and cats. This is due to the difficulty obtaining feline blood products, especially for type B cats or those with crossmatch incompatibilities.
Dog-to-cat blood transfusions have been reported in the veterinary literature and in the worldwide press. Certain countries with limited access to feline blood products report routine use of dog-to-cat blood transfusions, often as a first-line option for a feline patient in need of blood. Although there is limited published evidence on the efficacy of xenotransfusions in cats, a recent summary describes what we know thus far.
The main take-aways for dog-to-cat xenotransfusion are as follows:
- Cats do not seem to have naturally occurring antibodies against canine red blood cell antigens. This means that compatibility testing such as crossmatch testing does not demonstrate evidence of hemolysis or agglutination of canine red blood cells in the serum or plasma of previously non-transfused cats.
- Cats that receive a single transfusion of canine whole blood or packed red blood cells do not demonstrate severe acute adverse reactions.
- Anemic cats that receive a canine blood transfusion demonstrate clinical improvement within hours of the transfusion as demonstrated by a change in mucous membrane colour, heart rate, respiratory rate, and mentation.
- Cats that receive a canine blood transfusion develop antibodies against canine red blood cells that are detectable within 4-7 days. These antibodies result in delayed hemolysis of the transfused canine red blood cells. On average, the lifespan of transfused canine red blood cells to feline recipients is 3.6 days compared to approximately 30 days for transfused feline red blood cells.
- Any repeated transfusion of canine blood to a feline recipient more than 4 days after the first xenotransfusion will cause an anaphylactic reaction that frequently results in death.
Having witnessed or performed xenotransfusion in a handful of my feline emergency and critical care patients, I can say that the short-term effects are positive. However, this procedure should be considered a temporary band-aid in situations where compatible feline blood products are not available. In cases with blood loss or hemolysis that does not resolve within 24-72 hours, most feline xenotransfusion recipients require additional transfusions.
If you do choose to perform a xenotransfusion in your practice, please consider the following recommendations:
- Ensure that the cat has not been administered canine blood previously.
- Determine that the cat is likely to die within 6 hours without a blood transfusion.
- Obtain written or verbal consent from the owner with explicit instructions that the next time their cat presents to a hospital for emergency care, they inform the veterinarian that their cat has received a canine blood transfusion.
Ultimately, while no veterinarian should be criticized for administering canine blood to a feline patient, it is important to rule out the possibility of a compatible feline blood transfusion and to obtain informed consent from the owner.
Written by Marie Holowaychuk, DVM, Dipl. ACVECC who is a volunteer member of the Canadian Animal Blood Bank Board and co-editor of the Manual of Veterinary Transfusion Medicine and Blood Banking. She also passionately advocates for the mental health and wellbeing of veterinary professionals (www.marieholowaychuk.com).
