Haematology 13: Blood Transfusions 1

Question 1

What happens in Haemolytic disease of the newborn ?

Answer 1

• RhD -ve mother has a RhD positive child and comes into contact with the blood during pregnancy/ or has a RhD +ve blood transfusion.
• The mother now makes anti-D
• The next baby is RhD +ve and this time the anti-D antibodies (IgG) cross the placenta
• This causes a delayed haemolytic reaction

Question 2

How does indirect antiglobulin technique work to screen blood ?

Answer 2

• Blood recipient’s plasma is put into test tube (contains recipient antibodies)
• Blood donor’s red cells are added to the test tube (has antigens)
• If the recipient has antibodies against the donor’s red cells they will form antigen-antibody complexes
• Coombs antibody is added (anti-human antibody)
• This causes cross linking if immune complexes are present
• if agglutination takes place the blood is not matched

Question 3

What is the universal donor group for RBC ?

Answer 3

O- (no antigens on cells)

Question 4

What is the universal donor group for plasma ?

Answer 4

AB (no antibodies in plasma)

Question 5

Which method of blood transfusion is more acceptable for jehova’s witnesses ?

Answer 5

Cell salvage (collection, filtration and return of blood lost during surgery)

Question 6

Why do patients with immunosuppression require irradiation of blood products ?

Answer 6

The donor lymphocytes can start reacting to self antigens and mount an immune response

This is known as transfusion associated graft versus host disease (TA-GvHD)

Question 7

Which immune deficiency causes severe allergic reactions to donor blood plasma ?

Answer 7

IgA deficiency

Question 8

Name 2 haematological diseases in which platelet transfusion is strongly contraindicated ?

Answer 8

HIT - heparin induced thrombocytopenia

TTP- thrombotic thrombocytopenic purpura

Question 9

What is prothrombin complex concentrate (PPC) ?

Answer 9

A blood product containing vitamin K dependent clotting factors 10, 9, 7 and 2