But don’t think you have to run out and get a medic alert bracelet so you’ll be prepared in case of an accident. Dog blood types are designated by the acronym DEA (dog erythrocyte antigen) and a number (DEA 1, DEA 2, DEA 3 and so on).
DEA 1 has two subtypes: 1.1 and 1.2. DEA 1.1 positive is the most common dog blood type, and dogs with this type are considered universal recipients. Dogs with blood that is negative for both 1.1 and 1.2, and dogs with DEA 4, are considered universal donors.
DEA 1.1 positive is the most antigenic blood in dogs and the most likely to cause serious problems if it’s transfused into a non-compatible recipient. Fortunately, unlike people, dogs rarely have antibodies against other blood types, so it’s usually safe to give a dog a blood transfusion without knowing its blood type first. One time. That’s why he doesn’t need a medic alert bracelet—unless he’s already had a transfusion.
Dogs that have received a previous transfusion have used up their “one free transfusion” card, because that transfusion may have activated antibodies that can now react fatally with a subsequent transfusion. If a dog has received a previous transfusion, unless it was less than three days ago, its blood must be cross-matched with a donor. In fact, females that have previously whelped a litter are also at higher risk and should always be cross-matched before receiving blood.
As with people, dogs may need a transfusion following blood loss from trauma or during surgery. They may also need it in cases of immune mediated hemolytic anemia. Where does the blood come from? You may not have seen the doggy bloodmobile parked outside the veterinary hospital, but that’s not because doggy blood donors aren’t needed. Most veterinary clinics keep their own blood donors in-house, either a clinic dog that lives there, the veterinarian’s dog that comes to work every day, or a network of client dogs that have been volunteered to be “on call.”
Blood donors have to be fairly large (no sense in sucking a Chihuahua dry to try to save a Saint Bernard!), calm enough to take blood from (it takes about fifteen to twenty-five minutes, using the jugular vein), free of blood parasites (they are routinely checked), and have red-cell–rich blood. The breed of choice is the Greyhound, because they meet all these criteria, and because there are usually Greyhounds in need of adoption from race tracks. Greyhounds can be universal donors, meaning their blood can be used for any dog, no matter its blood type. In addition, Greyhounds have blood that is densely packed with red blood cells in comparison with other dogs. For example, a common measure of red blood cells, the hematocrit, averages around 35% in most dogs, but runs around 45 to 60%. That’s more bang for the buck, and helps anemic dogs get well faster. On the other hand, they tend to have fewer platelets than other breeds, so may not be the choice for a platelet deficient dog. Many vets will keep an adopted Greyhound as a donor for several months, then find it a home, replacing it with another dog from the track, so each dog eventually gets his chance at a home life.
Compatible blood can last three to four weeks in the recipient’s body. An artificial blood, made from cow hemoglobin, is also available and has the advantage of being easily stored and readily available. However, it doesn’t last in the recipient’s body only as long.
Can your dog be a donor? Many veterinarians offer free bloodwork and parasite testing to clients who offer their dogs as on-call donors. It’s a good deal—and your dog could be a life saver!
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