Lecture 6 9/5/24

Question 1

What is a blood group?

Answer 1

related group of antigens on the RBC surface

Question 2

What is a blood group antigen?

Answer 2

specific antigens within a blood group

Question 3

What is a blood type?

Answer 3

phenotypic expression of a blood group

Question 4

What are acquired alloantibodies?

Answer 4

antibodies produced after exposure to an RBC antigen not present on the individual’s own cells

Question 5

What are naturally-occurring alloantibodies?

Answer 5

antibodies produced without prior exposure to RBC antigens

Question 6

Which conditions can lead to acquired alloantibodies?

Answer 6

-blood transfusion
-pregnancy
-blood-derived products

Question 7

What are the consequences of alloantibodies?

Answer 7

-agglutination
-hemolysis

Question 8

What are the clinical implications of alloantibodies?

Answer 8

-transfusion reactions
-neonatal isoerythrolysis

Question 9

What are the characteristics of major transfusion reactions?

Answer 9

-recipient has antibodies against antigen on donor RBCs
-life-threatening
-can cause intravascular hemolysis, hypotension, and DIC
-risk on first transfusion

Question 10

What is the main characteristic of minor transfusion reactions?

Answer 10

can occur even with compatible blood typing and crossmatching

Question 11

What are the characteristics of neonatal isoerythrolysis?

Answer 11

-most common in foals, also seen in kittens
-occurs in neonates who acquire antibodies against their own RBC antigens through colostrum
-antigen-negative dam is bred to antigen-positive sire

Question 12

What is blood typing?

Answer 12

detection of specific antigens on RBCs

Question 13

What is crossmatching?

Answer 13

detection of antibodies in the serum of one animal that bind to antigens on RBCs from another animal

Question 14

What are the characteristics of blood typing?

Answer 14

-whole blood sample used
-reagent contains antibodies against a specific RBC antigen
-positive reaction leads to agglutination
-negative reaction shows no agglutination

Question 15

What are the most clinically important blood groups?

Answer 15

dogs: DEA 1; no naturally occurring antibodies
-cats: AB system with types A, B, AB; naturally-occurring antibodies are common
horses: Aa and Qa: most antigenic

Question 16

What result is seen in crossmatching if the two animals are incompatible?

Answer 16

agglutination and/or hemolysis

Question 17

What are the two samples used in a major crossmatch?

Answer 17

-donor RBCs
-recipient serum

Question 18

What are the practical implications of blood typing and crossmatching in horses?

Answer 18

-blood typing for horses is not available in house and is rarely done at labs
-must rely on crossmatching when performing transfusion medicine
-want to screen horses that enter blood donor programs; prefer horses negative for Aa, Qa, Ac, and Ca

Question 19

What are the practical implications of blood typing and crossmatching in dogs?

Answer 19

-typically do not have naturally-occurring antibodies to RBC antigens
-crossmatching is almost always compatible for first transfusion
-blood typing and crossmatching recommended for subsequent transfusions

Question 20

What are the practical implications of blood typing and crossmatching in cats?

Answer 20

-often have naturally-occurring antibodies
-always blood type, even before first transfusion

Question 21

What are the characteristics of crossmatch diagnosis of neonatal isoerythrolysis?

Answer 21

-uses foal RBCs and mare serum
-agglutination/hemolysis indicates positive result for NI