Blood typing is mandatory before every transfusion in both species; crossmatching requirements differ by species and transfusion history.

In dogs, DEA 1 typing is the minimum pretransfusion requirement. Seven canine blood groups are recognized (DEA 1, 3, 4, 5, 6, 7, and 8), plus the more recently described Dal, Kai 1.1, and Kai 1.2 antigens.Journal of Vete… DEA 1 is the most clinically important due to its strong antigenicity and near-equal distribution of DEA 1-positive and DEA 1-negative dogs across many breeds.Journal of Vete… Dogs are generally considered to lack clinically important naturally occurring alloantibodies, with the possible exception of anti-DEA 7, meaning a first transfusion in a typed, never-previously-transfused dog carries lower immunologic risk than in cats.Journal of Vete…

Crossmatching in dogs is required — not optional — in specific circumstances. A crossmatch is indicated when transfusion history is unknown, when a prior transfusion was given more than 4 days before the current one, or following a hemolytic transfusion reaction.Journal of Vete… Even when DEA 1-matched blood is used, crossmatch incompatibilities have been detected 26 days after transfusion, indicating alloantibody formation against non-DEA 1 antigens; crossmatching is therefore required after any first transfusion even when DEA 1 typing was performed.Journal of Vete… Major crossmatch incompatibilities occur in 17% of transfusion-naïve dogs when tested against a panel of donors, though all dogs in that cohort were compatible with at least one of three potential donors.Journal of the… Dogs receiving crossmatch-compatible blood had a significantly greater post-transfusion hematocrit increase (12.5 ± 8.6%) compared to dogs transfused without crossmatching (9.0 ± 4.3%).Journal of the… Given the potential for immediate or delayed hemolytic reactions and shortened RBC lifespan, crossmatching all dogs prior to transfusion is recommended when possible.Journal of the…

In cats, AB blood typing is essential before every transfusion. The AB system is the major feline blood antigen system, with type A most prevalent, followed by B and AB.Journal of Feli… Type B cats virtually all carry high-titer anti-A alloantibodies, and as little as 1 mL of type A blood can cause acute, potentially fatal hemolytic reactions and anaphylactic shock in a type B recipient.Journal of Feli… In type A cats, 30% carry high-titer anti-B antibodies capable of causing severe hemolysis if type B blood is administered; the remaining 70% have low titers.Journal of Feli… Type AB cats lack antibodies against A or B antigens but should receive AB-type blood; when AB is unavailable, washed type A blood is used to minimize minor post-transfusion reactions.Journal of Feli… Point-of-care immunochromatographic strip kits provide rapid, accurate AB typing equivalent to laboratory flow cytometry.Journal of Vete…

Crossmatching is recommended before every feline transfusion, including the first. The MikMik antigen system carries naturally occurring anti-MikMik alloantibodies in some cats; typing for MikMik is not feasible due to lack of reagent availability, making crossmatching the only means of detecting this incompatibility.Journal of Vete…+1 Non-AB crossmatch incompatibilities have been identified in 29% of transfusion-naïve cats in one US cohort.Journal of Vete… Cats receiving type-specific, crossmatch-compatible packed red blood cells (pRBCs) show a significantly greater post-transfusion PCV increase compared to cats receiving typed but non-crossmatched pRBCs.Journal of Vete… The antiglobulin-enhanced gel column (AGC) crossmatch detects additional non-AB incompatibilities beyond those identified by the standard gel column method — 14 additional incompatibilities were identified exclusively by AGC in one study of non-transfused domestic shorthair cats.Journal of Vete… A crossmatch is universally required when a cat has received a transfusion 4 or more days prior to the current one.Veterinary Clin…

Post-transfusion monitoring follows a standardized schedule for both species. Vital signs are assessed every 15 minutes during the first hour, then hourly until transfusion completion, then at 15 minutes, 1 hour, and 24 hours after completion.MSD Vet Manuals PCV is assessed at transfusion completion to evaluate efficacy.MSD Vet Manuals

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