Blood Transfusion

Question 1

Describe the blood group transfusion process

Answer 1

A has anti B Antigens (Igm) so if come into contact = agglutination (that’s how you test blood type too (see agglutination))therefore fatal. vice versa

A codes of N-acetyl galactosamine and fructose stem
B codes for enzyme that adds galactose

A + B are co-dominant and O is recessive

A - 42%
B - 8%
O - 47%
AB - 3%

Question 2

Describe the important of RH

Answer 2

RhD is the most important: if positive then you have D and also anti-D antigens (after exposure so pregnant and blood transfused). O negative is the safest and AB positive is never given rarely.

In pregnant ladies: IgG causes haemolysis of foetus > anaemia and increased bilirubin

Question 3

Describe the components of blood when collected and how it’s separated

Answer 3

When collected it is put with anticoagulant. The whole bag isn’t donated only parts (more efficient and fluid overload for patient), this is because some components degenerate too quick and some require certain conditions

Centrifuge the bag and red cell in the bottom then platlets then white cell then plasma.

If you freeze plasma within 6 hours of donation then you can preserve all coagulation factors (FFP) and then overnight in 4 degree fridge it will seperate into cryoprecipitate (fibrinogen, F8, VWF, FB, and fibronectin)

Question 4

Describe the use of red cells, FFP, cryoprecipitate and platlets

Answer 4

1. Red cells: 1 unit from 1 donor and at 4 degrees up to 5 weeks and needs to be filtered to remove cell debris and fibrinogen
2. FFP: stored at -30 degrees within 6 hours for 3 years, need to be thawed at room temperature and usually 3 units. (Need to know blood type because antigen present). Used if people are bleeding and need anticoagulant, reversal of warfarin.
3. Cryoprecipitate: from FFP that is thawed at 4 degrees fridge overnight, contains fibrinogen and factor 8. Storage is same as FFP at -30 degrees for 3 years (usually 10 units), used if bleeding or hypo fibrinogen anaemia
4. Platlets: 1 pool from 4 donors, stored at 2z degrees, shelf life of 5 days, need to know blood type, and RhD sensitive