Crossmatching
Published on Mar 29, 2016
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PRESENTATION OUTLINE
CROSSMATCING
- To detect previously sensitized recipients and those with natural antibodies
- To prevent administration of incompatible blood
- 99 % cats - blood group A
- Abyssinian, Birman, British Shorthair, Devon Rex, Himalayan, Persian, Scottish Fold, and Somali, have a higher frequency of blood group B
- incompatible transfusion in cats results in rapid destruction of transfused cells
MIC ANTIGEN
- present in some cats, and naturally occurring antibodies are present in cats that lack the mic antigen
- crossmatching should be performed for cats before the first transfusion
- In dogs Crossmatching is only used with subsequent transfusion, no naturally occurring antibodies
MAJOR CROSSMATCH
- detects antibodies already present in recipient plasma
- Anticoagulant is added to blood samples from donor and recipient
- donor RBCs are washed 3 times with 0.9% saline, and a 4% RBC suspension in saline is made from the washed cells
- combining equal volumes (0.1 mL) of the donor RBC suspension and recipient plasma
- samples are incubated, centrifuged, and evaluated for hemolysis or agglutination
EVALUATION
- evaluated by comparing the color of the supernatant with control sample
- then gently shaken until all cells in have returned to suspension
- the degree of cell clumping is compared with the control sample
- negative, or compatible - plasma is clear and the RBCs are readily suspended
- positive, or incompatible - hemolysis or hemagglutination or both
MINOR CROSSMATCHING
- reverse of the major crossmatch, recipient cells are combined with donor plasma
- important only in species such as cats with clinically significant naturally occurring isoantibodies
- or if the donor has been previously transfused
- horses, those with previous pregnancies
Untitled Slide
- agglutination technique is adequate for the dog and cat
- horse has both agglutinating and hemolytic antibodies, procedures testing for both are warranted
- hemolytic test is necessary for cattle, sheep, and goats since they have minimal agglutinating antibodies
SAMPLE SUBMISSION
- Recipient samples for crossmatch or blood typing tests should be submitted in EDTA tubes
- Donor samples can be submitted in EDTA or as blood bag segments
