Dog & Cat Blood Type and Transfusion Compatibility Reference
Reference for canine DEA blood groups and feline A/B/AB blood types, including transfusion compatibility and when crossmatching is required. Switch species at the top of the table.
Canine blood groups (DEA)
| Topic | Details |
|---|---|
| System | DEA (Dog Erythrocyte Antigen). DEA 1 (positive/negative) is the most clinically significant and most immunogenic antigen. |
| First transfusion | Dogs do NOT have naturally occurring alloantibodies against DEA antigens they lack. An unsensitized dog's first transfusion is relatively low-risk even without typing/crossmatching - though typing is still best practice. |
| Subsequent transfusions | A dog that has been transfused before (or a bitch who has whelped, in rare cases) can become sensitized and MUST be crossmatched before any subsequent transfusion, since a delayed or acute hemolytic reaction becomes possible. |
| Universal donor | DEA 1.1-negative dogs are traditionally treated as the "universal donor" since DEA 1.1-positive blood given to a sensitized DEA 1.1-negative recipient is the most clinically significant mismatch reaction. |
| Recommendation | Type all donors and, ideally, crossmatch all recipients, especially any dog with unknown or prior transfusion history. |
Always confirm compatibility with a blood type test and, where indicated, a major/minor crossmatch before transfusion - this reference does not replace in-house or reference-lab typing.
Frequently asked questions
Why is cat blood typing more urgent than dog blood typing before a first transfusion?
Cats have naturally occurring alloantibodies from birth, so a mismatched transfusion can cause a severe, potentially fatal acute hemolytic reaction on the very first transfusion. Dogs lack naturally occurring alloantibodies against DEA antigens they don't have, so an unsensitized dog's first transfusion is comparatively low-risk.
What is the "universal donor" concept in dogs?
DEA 1.1-negative blood is traditionally used as the safer default donor blood, since DEA 1.1 is the most immunogenic and clinically significant canine antigen - though typing and crossmatching remain best practice for every transfusion.
Which cat breeds have a higher rate of Type B blood?
British Shorthair, Devon Rex, Cornish Rex, and Persian/Exotic Shorthair lines carry meaningfully higher Type B prevalence than the general cat population.
Do dogs ever need to be crossmatched?
Yes - any dog with a prior transfusion, unknown transfusion history, or that has whelped should be crossmatched, since sensitization can occur after first exposure to a mismatched antigen.