Blood Typing in Dogs
Blood typing is a test that determines the blood type of an animal. Like people, dogs and cats have different blood types. Blood typing can be crucial prior to a blood transfusion and determining the blood type can help reduce the risk of transfusion reactions. Since blood types do not change, this test is only needed once in a pet's life, as long as the results are recorded and readily available should future transfusions be needed.
If the animal has a disease that results in agglutination of the blood, blood typing cannot be accurately performed.
What Does Blood Typing Reveal?
A blood typing reveals the blood type of the animal. Determining the blood type is an important aspect of blood transfusions. As with people, transfusion reactions can occur if a different blood type is administered. This is especially true in cats.
Cats have three blood types – A, B and AB. There is no universal donor in cats. Despite the fact that about 90 percent of cats in the United States are type A, the rare type B cat can have a very serious and even fatal reaction if type A blood is administered. The same can occur in type A cats given type B blood. The very rare type AB cat can tolerate a transfusion from either type.
In dogs, DEA 1.1 (Dog Erythrocyte Antigen) has been found to be the part of the blood type most likely to cause a transfusion reaction. The blood type in dogs is either DEA 1.1 positive or DEA 1.1 negative. There are however, other parts to the canine blood type, including DEA 1.2, DEA 3, DEA 4, DEA 5 and DEA 7. In order to determine the full blood type, blood needs to be submitted to a special laboratory.
How Is Blood Typing Done?
In order to perform a blood typing, your veterinarian must draw a blood sample. One drop of blood is placed in a well on a special card, impregnated with certain proteins. A drop of blood typing fluid is placed on the blood drop and mixed, and the fluid is rocked on the card for about one minute. The fluid is then examined for agglutination, which appears as clumping and resembles ground red pepper. In dogs, if agglutination is present, the dog is DEA 1.1 positive.
In cats, two wells are used. If agglutination appears in the A well, the cat is type A. If agglutination occurs in the B well, the cat is type B. If agglutination occurs in both wells, the cat is type AB. If no agglutination is noted, an error has occurred and the test should be repeated. Test results are typically available within 10 minutes.
Some diseases and disorders result in agglutination of the blood. In these patients, it is not possible to determine the pet's blood type in a hospital setting. Their blood may need to be submitted to a special laboratory able to detect the blood type despite the presence of naturally occurring agglutination.
For dogs, a more extensive blood type may be needed. Since dogs have multiple parts to their blood type, the blood is submitted to a specific laboratory that is able to determine the dog's entire blood type. This is not the case in cats. If your veterinarian is unable to perform the test in the hospital, a blood sample may be submitted to a laboratory for analysis. Test results may not be available for up to 1 to 2 days.
Is Blood Typing Painful?
Any pain involved is associated with the collection of the blood sample, since a needle is used to pierce the skin and enter a blood vessel to draw the sample. As with people, the pain experienced from a needle will vary from individual to individual.
Is Sedation or Anesthesia Needed for Blood Typing?
Neither sedation nor anesthesia is needed in most patients; however, some pets resent needle sticks and may need tranquilization or ultrashort anesthesia.