What is the purpose of doing crossmatching prior to blood transfusions
To detect serological incompatibilities between donors and recipient prior to transfusion
What can serological incompatibilities result in when doing a blood transfusion
Acute immune mediated transfusion reactions
When should dogs be crossmatched before transfusions
Unless they have autoimmune disorders they can be cross matched before recieving a 2nd transfusion more than 4-7 days after their first one should be crossmatched
Why don’t we crossmatch all dogs prior to transfusions
Because they don’t have naturally occuring alloantibodies
Why should we crossmatch all cats before doing a transfusion
Because they have natual occuring alloantibodies that can result in an increase potential for serious transfusion reactions
What are the types of crossmatches
Major, minor, and control
What is major crossmatching
Screening for the presence of existing recipient antibody to the RBC antigens of the donor requiring mixing the recipient plasma w/ the donor’s RBCs
What is the most important type of crossmatch and why
Major crossmatching because it mimics what is happening when a patient is transfused
What is minor crossmatching
Allows for detection of existing antibody in the donor plasma against the recipient RBC antigen requiring mixing the recipient RBC and donor plasma
What is control crossmatching
A required process because recipients may have immune mediated hemolysis and or agglutination that will interfere w/ results of crossmatch requiring mixing the recipient plasma and recipient RBC
When is haemolysis assessed when crossmatching
By viewing the plasma component immediately after centriuging the samples
What groups of haemolysis indicates that the crossmatch is positive and the donor should not be used for the recipient
2+ to 4+ haemolysis
What stage of haemolysis indicates that the crossmatch is negative and the donor can be used on the recipient
1+ and negative
When is macroscopic agglutination assessed when crossmatching
By gently agitating the tubes and assigning a score based on the red cell movement/separation
What scores of macroscopic aggluntination indicate a positive result and the donor should not be used for the recipient
2+ to 4+
What level of macroscopic agglutination indicates a negative result so the donor can be used on the recipient
1+ and negative
