Blood groups Flashcards
What are blood groups
Determined according to antigens expressed on surface of erythrocytes
Alloantibodies are specific antibodies directed against erythrocyte antigens present in same species but not individual
Alloantibodies can be acquired or occur naturally
Describe dog blood groups
Number of different blood types but pen side tests only test for type DEA1.1
Blood type can be associated with breed
Rotties always DEA1.1 +ve
Labradors often DEA1.1. +ve
Greyhounds often DEA1.1 -ve
Describe cat blood groups
3 groups: A, B & AB (rare)
Type B cats receiving type A:
Massive intracellular haemolysis of donor blood
Can occur following small volumes
May be fatal
Type A receiving type B:
Milder clinical signs
Low half life of RBCs
PCV will fall to pre-transfusion levels within days
AB can receive any blood
Describe horse blood groups
7 blood groups (A, C, D, K, P, Q, U)
Mares that have been pregnant with foal that has different blood group become sensitised to foal’s blood & produce antibodies
Antibodies ingested with colostrum & attack RBCs of any future foals of same blood type that mare has been sensitised to -> neonatal isoerythrolysis
Donors should thus ideally be geldings
Aa, Qa & Ca are more immunogenic blood groups – often used as donors
How are blood groups tested
Detects antigen pattern on erythrocyte surface
Doesn’t determine presence of alloantibodies
Snap tests can be used for dogs & cats
Blood typing cards can also be used for dogs
Antibodies in paper cause agglutination
Blood cross matching:
Assess blood compatibility between donor & recipient
Major cross match: detects if recipients serum contains AB against donor
Minor cross match: detects if donor serum contains AB against recipient RBC
When should you transfuse
Clinical condition of patient
PCV <10%
PCV fallen rapidly to <20% dogs or <15% cats
During surgery in case of major haemorrhage
How much should you transfuse
2ml whole blood/kg body weight raises PCV by 1%
V = W x F X (End PCV – current PCV) / donor PCV
F = 85 in dogs, 60 in cats
What are blood donor criteria
Between 1 & 8 years old
Healthy
Good PCV
Fully vaccinated & wormed
Good temperament
Never had blood transfusion
Never travelled abroad
Female donors no previous pregnancy
