Frequently asked questions for the QuickVet®/ RapidVet® DEA 1.1™ test
What is Canine DEA 1.1?
Currently eight specific antigens have been identified on the surface of the canine erythrocytes. The internationally accepted canine blood group system, the Dog Erythrocyte Antigen (DEA), is based on these antigens. It currently characterizes eight common blood groups, the antigens DEA 1.1, 1.2, 3, 4, 5, 6, 7, and 8.
As occurred in human medicine, new antigens are however now being discovered on the red cells of dogs. One, DAL, has been reported and is the subject of journal articles. These are often breed specific and thus can be considered rare.
The DEA1.1 blood group is the most significant blood factor in the dog. The DEA1.1 blood group is highly antigenic and is the primary lytic factor in canine transfusion medicine. Although all of the blood group
antigens are capable of stimulating formation of alloantibodies, DEA 1.1 has the greatest stimulation potential. Thus most reactions resulting from the transfusion of incompatible cells occur when DEA 1.1 positive blood is given to a DEA 1.1 negative recipient.
Clinically significant reactions to DEA 1.2 may occur but are less severe. DEA 7 may be a factor in transfusion reactions, but since it is a cold agglutin and a naturally occurring isoantibody, it is considered to have very low clinical significance.
The remaining antigens are considered to cause clinically transfusion problems. It is estimated that 40% of all dogs are DEA 1.1 positive.
Why test before a transfusion?
While it is broadly true that dogs do not posses alloantibodies to incompatible blood groups and thus will generally tolerate well an initial incompatible transfusion, sound practice of veterinary medicine dictates that such transfusions be avoided. The half life of the transfused incompatible cells will be quite short and, thus, the intended therapeutic result may not even be attained. Also, the potential future needs of the canine patient must be considered. Antibodies resulting from a transfusion of incompatible blood may form days and will have long-term viability. This eliminates the option of using incompatible blood in a future emergency situation.
In addition, antibodies developed in bitches by sensitization resulting from transfusion of incompatible blood groups must be of special concern to breeders. Since antibodies are present in the colostrum, bitches with alloantibodies to a given blood type should not be bred to a sire possessing that blood group if they are expected to nurse the resulting puppies. The nursing puppies will develop isoerythrolysis and may be susceptible to disease or even die due to hemolytic anemia.
Ideally, all transfused blood would be DEA1.1 negative. However, until the concept of using blood rapidly available from commercial sources is more widely accepted, transfusion from dogs that are present in the area at the time of need will remain the norm. Because a number of dogs auto-agglutinate and because a very anemic dog may give equivocal results, typing prior to an urgent need for the information is indicated. Identifying a particular dog as DEA1.1 positive or negative at birth greatly simplifies future decision making. A DEA1.1 positive dog can receive both DEA1.1 positive and negative blood. A dog that is DEA1.1 negative should not receive DEA1.1 positive blood.
Are there other tests required before a transfusion?
It is recommended that a cross match is also performed before a transfusion.
How should a DEA 1.1 Negative dog be treated in regards to transfusions?
A DEA 1.1 negative dog can be donor to all other dogs, but only if the cross match shows that the blood is compatible. If the dog is to be the recipient it may only receive DEA 1.1 negative blood.
Why are some results inconclusive?
As the number of DEA 1.1 alloantibodies on the erythrocyte varies greatly from dog to dog, some dogs have so few DEA 1.1 alloantibodies that a positive identification is not possible. However they may still potentially induce a hemolytic reaction and is consequently therefore characterized as inconclusive. As to the diagnostic implication a dog that is typed as inconclusive must, if it is the recipient be regarded as a DEA 1.1 negative dog, and if it is the donor be regarded as DEA 1.1 positive.
How should a DEA 1.1 Positive dog be treated in regards to transfusions?
A DEA 1.1 positive can be donor to ONLY other DEA 1.1 positive dogs and only if the cross match shows that the blood is compatible. If the dog is to be the recipient it may receive both DEA 1.1 negative and positive blood.
Does the method of blood sample collection matter?
Proper technique for blood collection is essential for accurate results. Blood should be drawn as a-traumatically as possible in a syringe or EDTA tube. Samples with visible clotting, hemolysis or debris should be discarded and a fresh sample obtained. The sample should be tested within 12 hours.
When would clinics use the Canine DEA 1.1™ test?
The practice of veterinary transfusion medicine has undergone tremendous growth in recent years, and as a result the understanding of the importance of identifying blood types has increased.
Clinics should therefore use the test for:
- Determination of blood type before a transfusion.
- As part of the pre-operation test panel to ensure that relevant information is on file if an emergency requiring a transfusion arises.
- Determination of blood type as part of routine testing so that the information is on file, the owner knows the blood type and the dog can carry a dog-tag with blood type information in the collar.
- Prior to breeding decisions.
What animals can be tested with the QuickVet®/ RapidVet® DEA 1.1™ test?
The QuickVet®/ RapidVet® DEA 1.1™ test only works with canine, as the blood type is specific to each species.