bloodtyping

alloantibodies

naturally occurring antibodies against the RBC antigens that they do not possess. species like cats, cattle, sheep, pigs. Those who lack it will develop new antibodies to the mismatched antigen. Breeding females should always be given properly matched blood to minimize the potential for the production of antibodies that can result in the destruction of a neonates rbcs.

dog blood types

more than a dozen blood groups have been described. (DEA) dog erythrocyte antigen followed by a number. Erythorcytes are designated as positive or negative for the antigen.

DEA 1

once considered to have three subgroups, but they are three different expressions of the same gene. DEA 1 elicits the greatest antigen response and causes the most serious transfusion reaction. 50% of dogs are positive for DEA1. Naturally occurring anti DEA 1 anti1 antibodies are not known to exist, the first transfusion of DEA 1 positive blood into DEA 1 negative may not result in an immediate reaction. symptoms may show up in a week of the transfusion. If a previous negative dog received a pos transfusion before then a serious reaction will occur in less than 1 hour with the next positive transfusion.

DEA 3,4,5,7

designated other major blood groups. The ones clinically significant are DEA 1 and 7.

cats

One blood group system has been identified in cats, and it has been designated the AB system. The blood groups of cats are A, B, and AB, Few cats have group AB blood. The vast majority of cats in the United States have group A blood, which probably accounts for the low incidence of transfusion reactions in cats. Type B blood is found in certain purebred breeds (e.g., Devon Rex, British shorthair) and certain geographic areas (e.g., Australia). Unlike dogs, cats have naturally occurring antibodies to the erythrocyte antigen that they lack. Type B cats have strong anti-A antibodies, whereas type A cats have weak anti-B antibodies. Transfusing type B cats with type A blood may result in a serious transfusion reaction and death. Thus, blood for transfusions in purebred cats should be selected by typing or crossmatching. Mik, which is another blood cell antigen, has also been described in cats. Neonatal isoerythrolysis has been documented in type A and type AB kittens of type B queens with naturally occurring anti-A antibodies.

cattle

Eleven blood groups have been described in cattle, and these have been designated A, B, C, F, J, L, M, R, S, T, and Z. Group B is polymorphic, with more than 60 different antigens. Anti-J antibodies are the only common natural antibodies in cattle. J negative donors may be used to minimize transfusion reactions.

Sheep and Goats

Seven blood group systems have been identified in sheep, and these have been designated A, B, C, D, M, R, and X. Similar to cattle, the B system is highly polymorphic. Naturally occurring R antibodies may be present. Neonatal isoerythrolysis may occur in lambs that are administered bovine colostrum. This is caused by the presence of antibodies to sheep erythrocytes in bovine colostrum. Five major systems have been identified in goats and designated A, B, C, M, and J. Naturally occurring J antibodies may be present.

horses

More than 30 blood groups have been described in eight major blood group systems in horses; the major groups have been designated A, C, D, K, P, Q, T, and U. Naturally occurring antibodies do exist, but antibodies may be present as a result of vaccinations that contain equine tissue or transplacental immunization. Crossmatching should be done before the first transfusion in a horse, because transfusion reactions in horses are commonly fatal. The mare-foal incompatibility test is a crossmatching procedure that detects the presence of antibodies in mare serum (or colostrum) to foal erythrocytes to confirm or prevent neonatal isoerythrolysis.

Tube method blood typing

the gold standard for blood typing. The tube method for determining blood type requires the use of antisera, which consist of antibodies specific for each possible blood type of a given species. Commercial antisera for canine and feline group testing are available for a few canine and feline blood groups (Box 51.1). The tube method requires repeat testing. collection of a whole blood sample using ethylmediaminetetraacetic acid (EDTA), heparin, or acid-citrate-dextrose anticoagulant. The blood is centrifuged at 1000 g for 10 minutes. After the removal of the plasma and buffy coat, the enterocytes are washed three times in a saline solution, centrifuged, and resuspended. The RBC suspension is distributed among as many tubes as required for the number of blood type antisera being tested. A small amount usually 0.1 mL) of the antisera is added to the appropriately labeled tube. The tubes are incubated for 15 minutes at room temperature and then recentrifuged for 15 seconds at 1000 g. Each tube is examined macroscopically and microscopically for evidence of hemolysis or agglutination. Weak positive results may require repeat testing. The blood typing of large animals is impractical for routine analysis before transfusion. Literally thousands of different antisera would be required because of the large number of different blood groups in the sheep, cow, and horse.

The Card Agglutination Test

Blood samples used to perform the card-based assay must not already show evidence of autoagglutination, which is usually visible as clumps in the blood sample. Washing the RBCs with phosphate-buffered saline may help to salvage a sample that is showing evidence of agglutination.

The RapidVet-H Canine DEA 1 (DMS Laboratories)

is a blood-typing test card that is used to classify dogs as positive or negative for DEA 1. The typing card contains a monoclonal antibody specific to DEA 1. Each card has visually defined wells for the patient test and controls. One drop of EDTA-anticoagulated whole blood and one drop of phosphate-buffered saline are mixed on the lyophilized reagents within each well. In the DEA 1-positive test well, the monoclonal antibody forms an antiserum, which is then mixed with whole blood from the patient. If present, DEA 1-positive erythrocytes react with the antiserum to cause agglutination. The antiserum in the patient test well does not react with DEA I-negative erythrocytes. 

RapidVet-H (feline)

is a similar blood-typing test card for classifying feline blood as type A, B, or AB. The assay uses test wells that contain lyophilized reagent, which represents an antibody to the A antigen, and an anti-B antigen, which consists of a lectin. Erythrocytes from type A cats agglutinate with anti-A monoclonal antibodies (the A well on the card), and erythrocytes from type B cats agglutinate with anti-B solution (the B well on the card). Erythrocytes from type AB cats agglutinate with both anti-A and anti-B reagents. The third well on the card serves as an autoagglutination saline screen and must be negative for results to be valid. Samples are first screened for autoagglutination. If autoagglutination is present, the RBCs may be washed with phosphate-buffered saline and the autoagglutination screen repeated. If the autoagglutination result is negative, the typing test may be performed.

Immunochromatographic Assay

Several commercial test kits make use of the immunochromatographic test principle rather than agglutination. The control band detects a separate antigen on the RBCs. The canine test uses a paper strip impregnated with monoclonal anti-DEA 1 antibody and a second antibody to a universal RBC antigen as a control. An RBC solution diffuses up the strip, and if the cells express DEA 1, they concentrate in the area of antibody impregnation. The cells also concentrate in the area of the control antigen, thereby demonstrating that cells have successfully diffused up the length of the strip. The feline test works the same way; however, it has an area that contains an anti-A monoclonal antibody, an area that contains an anti-B monoclonal antibody, and a control antibody for a common feline RBC antigen, thereby allowing for the identification of blood type A, B, or AB.

CROSSMATCHING

In the absence of commercial antisera, crossmatching a blood donor and a recipient reduces the possibility of a transfusion reaction. The two-part procedure (i.e., major and minor crossmatching) requires a serum sample and a whole blood sample (Procedure 51.1). RBC suspensions, which are collected as for blood typing, are prepared. For the major crossmatching, a few drops of serum from the recipient are added to a few drops of washed packed RBCs from the donor. The mixture is incubated and then centrifuged. The macroscopic or microscopic presence of hemolysis or agglutination indicates a blood-type mismatch. The minor crossmatch is similar except that donor serum and recipient RBCs are used. Both procedures should be performed for all animals with unknown blood types that require transfusion. Two controls are used for the test, which consists of using donor cells with donor serum as well as recipient cells with recipient serum. Commercial test kits for crossmatching are also available.