Blood type DEA 1 in dogs

Dogs have several blood groups, named DEA (dog erythrocyte antigen) with a number. DEA 1 matters most for transfusions, so it is the group clinics and labs usually type. The result is positive or negative; it helps choose donor blood, but it does not cover every blood group a dog has.

SectionComplete blood count

SampleWhole blood with EDTA (purple-top tube); not frozen

Units—

On formsDEA 1.1

What it shows

Red blood cells carry markers on their surface called antigens, and a blood group is a set of such markers. Dogs have several blood group systems, named DEA (dog erythrocyte antigen) with a number: DEA 1, 3, 4, 5, 6, 7 and 8, plus others such as Dal. DEA 1 is considered the most clinically relevant, because it provokes the strongest immune response. Depending on the region, about 33–65% of dogs are DEA 1 positive.

Older forms may print DEA 1.1 or DEA 1.2: once thought separate, they are now known to be one antigen, DEA 1, present in different amounts.

Dogs, unlike cats, have no ready-made antibodies against DEA 1. A DEA 1 negative dog can form them after receiving DEA 1 positive blood, usually around 7–10 days after that first exposure. A later DEA 1 positive transfusion may then be destroyed quickly.

Higher than reference — what it may be a sign of

DEA 1 positive — the red cells carry DEA 1. It is a normal variant, not a sign of disease. A DEA 1 positive dog can receive DEA 1 negative red cells without incompatibility in this group.
Weak positive — DEA 1 is present in different amounts, so some reports grade it: negative, weak positive, or positive from 2+ to 4+. As a recipient, a dog with a weak positive result is advised to receive DEA 1 negative blood.

Lower than reference

DEA 1 negative — the red cells lack DEA 1; this is also a normal variant. Because such a dog has no natural antibodies against DEA 1, an acute reaction in this group generally needs an earlier sensitisation — a past transfusion of DEA 1 positive blood. After that, a new DEA 1 positive transfusion can be destroyed within minutes to hours instead of surviving about three weeks. That is why typing donors and recipients for DEA 1 before a transfusion is strongly recommended.

Look at together with

Crossmatch — the recipient’s blood is mixed with the donor’s to look for a reaction. Typing answers only about DEA 1; a crossmatch also picks up incompatibility in other groups. In dogs it is not required before a first transfusion, and is recommended when an earlier transfusion was more than 4 days ago.
Other groups — some DEA 3, 5 and 7 negative dogs do have natural antibodies; they cause delayed rather than acute destruction of donor cells. Dal negative dogs, more frequent among Doberman Pinschers, Dalmatians and Shih Tzus, are hard to match.
Haematocrit and hemoglobin — the numbers by which anemia, the usual reason for a transfusion, is judged.

Units and conversion

A blood type has no unit. The result is written as DEA 1 positive or DEA 1 negative; some reports add the strength — weak positive or 2+ to 4+ — and older forms may write DEA 1.1. Typing is done with card kits, where antibodies in the card wells make positive cells clump, or with strip (immunochromatographic) kits, which also detect weak DEA 1; these clinic kits agree well with laboratory methods. In the app the result is stored as text.

Reference range

What you see on your lab’s form is a type, not a range: DEA 1 positive and DEA 1 negative are both healthy variants. The result matters when a transfusion is planned or when a dog becomes a blood donor — typing all donors is advised. Whether a particular unit of blood suits a particular dog is decided by the vet, often with a crossmatch.

Cats and dogs

Cats

Cats do not have DEA groups: their main system is AB, with types A, B and AB. Cats carry ready-made antibodies against the type they lack, so for them typing is essential even before the first transfusion — see blood type in cats. Dog blood is given to a cat only when no compatible cat blood is available.

Dogs

How common DEA 1 is depends on breed: most Greyhounds are DEA 1 negative, while many Labrador Retrievers are positive. Neonatal isoerythrolysis (the mother’s antibodies destroying a newborn’s red cells) has been reported in puppies of a DEA 1 negative female who had been sensitised to DEA 1 positive cells and was mated to a DEA 1 positive male; the puppies absorb the antibodies with colostrum.

In the app

Add a lab form — Pet Tracker Space recognises the lines, keeps the form’s units and draws each indicator over time with your lab’s reference band.

Open the app

Sources

Updated 6 November 2026 · Mihail Ivanov, creator of Pet Tracker Space · Written with Claude and checked against the sources above.

This page explains what a lab value means. It is not a diagnosis and not a substitute for your veterinarian — only they can interpret results for your pet.