blood transfusion

Question 1

What do groups A and B have attached?

Answer 1

• extra sugar reside

Question 2

what does A gene code for? what about B gene?

Answer 2

A gene: N-acetyl galactosamine

B gene: Galactose

Question 3

describe structure of group O

Answer 3

just fucose stem, no extra sugar

Question 4

what is the universal donor/receiever?

Answer 4

OO- = donor
AB+ = receiver

Question 5

what antibodies are found in a person’s blood?

Answer 5

• person has antibodies against any antigen NOT present on their own red cell
• e.g. patient with group A, have antibodies against group B

Question 6

what is the antibody that reacts against miss-matched blood?

Answer 6

• IgM
• is a complete antibody
• when it reacts it causes a full complement cascade and haemolysis of red cells
• can be fatal
• also causes agglutination of red cells

Question 7

how is a person’s blood tested?

Answer 7

• by reaction it with known anti-A and anti-B reagents to test group
• donor of same group then selected and blood crossed matched to be sure (check for agglutination)

Question 8

What are RH blood groups?

Answer 8

• RHD positive or negative
• • having D-antigen on RBC
• -ve have no D antigen on RBC
• RhD is co-dominant
• 85% are RhD+, 15% are RhD-

Question 9

What are anti-D antibodies?

Answer 9

IgG

not as bad as IgM

Question 10

When can people who are RhD- make D antibodies after exposure to RhD antigen?

Answer 10

• by transfusion of RhD+ blood

- in women if pregnant with RhD+ child

Question 11

what are the implications of transfusing RhD+ blood to RhD- people?

Answer 11

• Pt must have RhD- blood in the future otherwise anti-D antibodies they have made from 1st transfusion would react
  = delayed haemolytic transfusion reaction

Question 12

what are the implications of a mother having RhD- blood anf the baby has RhD+?

Answer 12

• RhD- mother has anti-Antibodies made post transfusion
• in next pregnancy, has a child that is RhD+
• mothers IgG antibodies will cross placenta and attack child’s RBCs
  = haemolytic disease of new born

Question 13

how do you avoid both of these?

Answer 13

• transfuse blood of same RhD froup as pt
• can give RhD- to any pt
• O- blood used in emergency

Question 14

when you centrifuge blood, what is found at different levels?

Answer 14

• RBCs at bottom
• platelets middle
• plasma top

Question 15

how are red cells stored? how many units from a donor

Answer 15

• stores for 5 weeks at $C
• not normally given frozen as poor recovery upon thawing
• 1 unit/donor

Question 16

What is the storage of FFP? how much/ donor?

Answer 16

• 1 unit/ donor
• dose is 3 units
• stores for 2 years at -30C
• thaw 20-30 mins before use

Question 17

what are the implications for use of FFP?

Answer 17

• bleeding and abnormal coagulation tests results (PT and APTT)
• reversal of warfarin for urgent surgery

Question 18

What is cryoprecipitate formed from? what does it contain?

Answer 18

formed from frozen plasma thaw residue

contains fibrinogen and F8

Question 19

what is the storage and dose of cryoprecipitate?

Answer 19

• stored at -30C for 2 years

- 1 dose from 10 donors

Question 20

when is cryoprecipitste used?

Answer 20

• given for massive bleeding

- hypofibrinogenaemia

Question 21

how many donors does it take to get platelets? how is it stored?

Answer 21

• 1 pool from 4 donors or from ` donor by apheresis

- stored at 22C but constantly agitated for 5 days only

Question 22

what are the indications of use for platelets?

Answer 22

• bone marrow failure
• massive bleeding
• DIC
• surgery (pt has low platelets)
• cardiac bypass and pt on anti-platelets

Question 23

what are the different fractioned products?

Answer 23

• F8/9
• immunoglobulins
• albumin

Question 24

what must all blood be tested for?

Answer 24

• Hep B/C
• HIV
• HTLV
• Syphilis
• CMV

Question 25

what is Prion disease? How is it avoided?

Answer 25

• vCJD
• can be transmitted by blood transfusions
• as a precaution all plasma pooled to make fractioned products obtained from USA
• all blood components have white cell filtered out (white cells essential for uptake of vCJF prion into brain)