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blood bank

blood bank

Blood type

Blood groups are determined by the different antigenic markers on the surface of the erythrocytes. There are 8 blood groups in the canine species (Table 1) and there are, in addition, 25 or more antigenic erythrocyte factors to be standardized. Some of these are extremely rare and are not considered significant in practical medicine. The different groups are classified according to the DEA (dog erythrocyte antigen) system:


Of all the groups, the one with the most antigenic power and, therefore, the greatest probability of producing adverse reactions is the DEA-1.1 group. Approximately 25% of first transfusions from untyped donors to patients of unknown group develop anti-DEA-1.1 antibodies. Subsequent transfusions of blood positive for the DEA-1.1 antigen may cause adverse reactions.

Dogs negative for the DEA-1.1 factor will be ideal donors (“universal” donor, although this term has not been officially recognized). In 2007, a new canine antigen independent of the DEA system was described, the Dal antigen (described for the first time in a Dalmatian, although it is not exclusive to this breed). At the moment no relevant clinical importance has been demonstrated.

The canine species lacks preexisting alloantibodies against other blood groups. After the first transfusion, the time necessary for the body to make antibodies against the exogenous blood group is 4 or 5 days. For practical purposes, we can repeat a transfusion without checking the compatibility of donor and recipient before this period without expecting adverse reactions.
The development of anti-DEA-1 alloantibodies is especially problematic when the recipient is DEA-1 negative and receives a transfusion from a DEA-1.1-positive donor. Adverse effects include: hemoglobinemia, hemoglobinuria and thrombocytopenia due to hemolysis and DIC, leukopenia, fever, emesis, incontinence, urticaria and disorientation.

DEA-7 is a possible factor in transfusion reactions. This factor causes agglutination reactions in vitro at a temperature of 22ºC, but at 37ºC it dissolves. Antibodies that react at temperatures below 37ºC are normally considered to have a low risk of causing adverse effects, except when large quantities of fresh blood are transfused or the recipient patient is hypothermic.

In felines, the AB group system is recognized, in which we find the 3 types: A, B and AB. Group A is dominant over B, therefore only cats homozygous for B express this group. The frequency of feline blood groups varies greatly depending on the breed and geographical area, with group A being the most common and AB the rarest, having a frequency of less than 1%. (Table 2 and 3).

Unlike dogs, in cats we find natural alloantibodies against other blood groups. This requires checking from the first transfusion whether the patient is compatible, as we could cause serious adverse reactions.

Group B cats have potent antibodies against group A, which means that a B recipient receiving type A blood can develop serious incompatibility reactions. These isoantibodies can also cause neonatal isoerythrolysis. If a group B female has offspring with an A (dominant) male, A or AB kittens, upon ingesting anti-B colostral antibodies, can suffer serious hemolytic reactions, especially in breeds such as the British Shorthair, Sphynx, Devon Rex and Cornish.

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