Transfusion medicine

Question 1

4 major blood groups

Answer 1

A,B,AB,O

Question 2

what is a blood group in a molecular sense

Answer 2

enzymes on the surface of the erythrocyte

Question 3

what is an AB person in terms of antigen and antibodies

Answer 3

antigen - both A and B

ABs - non

Question 4

what happens in bad major blood group match

Answer 4

AB binds to RBC antigens > activates complement cascade > hemolysis

Question 5

what is major-side incompatibility

Answer 5

transfusion of incompatible RBCs

Question 6

what is minor side incompatibility

Answer 6

transfusion of incompatible plasma

Question 7

what happens if get intravascular complement activation

Answer 7

proinflammatory properties - fever, anaphylaxis, respiratory burst

Question 8

steps in incompatibility rxn

Answer 8

1. complement activation
2. TNF-a production
3. procoagulant activity
4. chemokine production

Question 9

what are minor blood groups

Answer 9

• antigens that do not have circulating ABs, but need to be activated if come into contact with
• less complement activation

Question 10

what happens in minor blood group transfusion

Answer 10

• delayed hemolytic fusion reaction

- still get hemolysis and degradation , but a slower process and often outside of the blood stream

Question 11

what is hemolytic disease of fetus

Answer 11

fetal RBCs enter the maternal blood stream and mother devs ABs to blood, which enters fetal blood stream

Question 12

what types of AB bind to major and minor blood group and significance of this

Answer 12

major - IgM - get pentameters and agglutination

minor - IgG - won’t agglutinate

Question 13

what is antiglobulin test

Answer 13

give and AB ABs that bind to IgG on RBC and cause them to agglutinate

Question 14

2 types of antiglobin tests and what they are for

Answer 14

direct (DAT) - tests RBCs- anti-Ig mixed with RBCs to see if they had ABs bound
indirect (IAT) - tests plasma - mix plasma wit RBCs, then anti-Ig mixed

Question 15

what is most important minor blood group

Answer 15

RhD - very immunogenic

Question 16

what 2 things to do for people Rh-

Answer 16

1. give Rh- blood

2. passively immunize women of Rh+ baby if they are Rh-

Question 17

when do we need to match for any other minor group than Rh

Answer 17

only if they already have the AB in their system

Question 18

what is group and screen test

Answer 18

group - patient cells checked for ABO and Rh groups and serum checked for ABs
screen - patient serum checked for alloABs by giving patient serum with panel of RBCs of known antigen types

Question 19

2 types of clincally insignificant ABs

Answer 19

1. those that only bind to cold blood

2. only bind weakly

Question 20

what is crossmatching

Answer 20

test patient serum against some of actual blood units to be used

Question 21

what is trauma blood

Answer 21

Oneg blood - has no major antigens - rare and in short supply

Question 22

what are 5 probs with blood banking and solutions

Answer 22

1. clotting - prevent with citrate
2. spoilage (use up metabolic reserve) - give glucose
3. contamination with bact - try to be sterile
4. supply - payment, altruism

Question 23

4 main components of a blood unit

Answer 23

1. RBC
2. plasma
3. WBCs
4. platelets

Question 24

adv of fractionating blood (3)

Answer 24

1. only give the components needed
2. can give smaller volumes
3. optimize storage conditions

Question 25

life and limiting factors for RBCs

Answer 25

1. 42 days at 1-6C

2. limiting factor for donations

Question 26

platelet shelf life

Answer 26

5 days - prone to shortages due to high demand

Question 27

plasma shelf life

Answer 27

can be frozen for a year

Question 28

what are fractionated blood products

Answer 28

abumin, factors, etc - expensive and get most from the US