Blood groups and crossmatching
Blood groups
On the surface of erythrocytes are various glycoproteins and glycolipids that act as antigens. Because of these isoantigens or agglutinogens, blood is categorized into various blood groups, each of which can have various blood types.
In humans, the most common blood groups are the ABO blood group and the Rh blood groups, whereas animals have a variety of different blood groups.Cattle have 11 major blood group systems, including A, B, C, F, J, L, M, R, S, T, and Z. The B group has over 60 different antigens. The J antigen is not a true antigen, but instead is a lipid found in body fluids that adheres to erythrocytes.
The antigen groups or blood types in dogs are known as the DEA system. They include DEAs 1.1,1.2, and 3-8. DEAs 1.1 and 1.2 account for 60% of the canine population. Dogs having DEA 1.1 or 1.2 are considered A-positive; other dogs are considered A-negative. A-negative dogs do not have antibodies against A-positive blood.
Cats have three AB blood groups. Type A is most common, accounting for 95% of short- and long-haired domestic cats. Type B is less frequent, and Type AB is rare. Cats with type A blood have antibodies against A isoantigens whereas type B cats have alloanti- bodies (i.e., antibodies found against antigens in some members of the same species) against B isoantigens.
There are seven blood groups in sheep, including A, B, C, D, M, R, and X. The B group is highly polymorphic, and the R system is similar to the J system in cattle.
Five blood groups have been identified in goats: A, B, C, M, and J, with J being similar to that of cattle.
Crossmatching
Crossmatching is a procedure to determine whether donor blood is compatible with the recipient's blood. There are two types of crossmatches. In major crossmatching, the donor erythrocytes are compared to the recipient serum to determine whether either acquired or naturally occurring antibodies are present in the recipient serum against the donor erythrocytes. Minor crossmatching compares donor serum to recipient erythrocytes, checking for preformed antibodies in donor serum that could hemolyze recipient red cells.
Minor crossmatching is less important since the donor serum is markedly diluted after transfusion, decreasing the risk of a significant reaction.