Blood Transfusion

Question 1

What is the minimum weight you have to be to give blood?

Answer 1

50kg

Question 2

What infections is donated blood tested for?

Answer 2

HIV (antibody +PCR)
HCV (antibody +PCR)
HBV (antibody +PCR)
HTLV (antibody)
Syphillis (antibody)

Question 3

What are the important points in storage of red cells?

Answer 3

• Refrigerated
• 35 day shelf life
• If removed for more that 30 mins must be either transfused or discarded.
• Must be transfused within 4 hours of leaving storage

Question 4

What are the important points in storage of platelets?

Answer 4

Stored at 22 degrees with continual agitation
Shelf life of 5 days
Transfuse within 1 hour

Question 5

What are the important points in storage of fresh frozen plasma?

Answer 5

Stored at -30 degress for up to 2 years.

Thawed prior to transfusion and transfused within 4 hours

Question 6

What chromosome is blood type (ABO) coded on?

Answer 6

9

Question 7

What chromosome is rheus blood type coded on?

Answer 7

1

Question 8

Why would you have irregular red cell antibodies such as anti kell?

Answer 8

These are not naturally occurring like anti A and Anti B and develop after previous exposure to red cells eg from transfusion or pregnancy

Question 9

What test do you use for testing for allo antibodies?

Answer 9

Indirect antiglobulin test

Question 10

Which antibodies mediate an acute immediate haemolytic reaction caused by ABO incompatibility?

Answer 10

IgM

Question 11

Why is an ABO incompatible transfusion so fast to occur? How does the reaction occur?

Answer 11

• IgM antibodies forma Membrane Attack complex which causes full activation of the complement cascade
• C3a and C5a are released which causes vessel dilation, histamine release and increases vascular permeability.
• MAC leads to rupture of transfused red cells.
• Thromboplastic materal from haemolysed red cells leads to indiscriminate activation of the coagulation mechanism and DIC
• Formation of bradykinin causes arteriolar dilation and increased vascular permeability which leads to hypotension.

Question 12

How long after a transfusion does a delayed haemolytic reaction occur?

Answer 12

5 - 10 days

Question 13

What antibodies mediate an urticarial reactions to a blood transfusion?

Answer 13

IgE

Question 14

What are the most common causitive bacteria in a bacterial transfusion reaction with red cells?

Answer 14

Pseudomonas

Yersinia

Question 15

What are the most common causitive bacteria in a bacterial transfusion reaction with platelets?

Answer 15

Staph
Strep
Serratia
Salmonella