Week 3 - Transfusion

Question 1

What happens when you go to donate blood?

Answer 1

• Donor questionnaire
• Positive donor identification
• Clean aseptic technique used
• Sample collection for viral testing
• Takes around 1 hour

Question 2

How much in a bag of red blood cells (vol and cost), storage?

Answer 2

• approx 260mL
• $399
• storage for 42 days in the fridge

Question 3

How much in a bag of fresh frozen plasma (vol and cost), storage?

Answer 3

• approx 280mL
• $182
• Storage for 1 year in freezer

Question 4

What to do before transfusing blood?

Answer 4

• Check patient details - Name, DOB, Hosp number -> make sure all these match patient’s wristband

Question 5

What are the goals of pretransufsion testing?

Answer 5

to Prevent:
- ABO incompatibility
- Clinically significant red cell alloantibodies

Question 6

Blood types and Compatability

Answer 6

Question 7

What happens if you add Anti-A antibodies to RBCs coated with A antigen?

Answer 7

it agglutinates

Question 8

What is an Antibody screen?

Answer 8

Patient plasma tested against 3 screening cells with known red cell phenotype

Question 9

What are the steps of an indirect antiglobulin test?

Answer 9

1. Patient serum/plasma +enhancer, +test RBC -> spin and read
2. Wash RBC
3. Add antiglobulin reagent -> spin and read
4. Confirm negative with check cells

Question 10

What is Crossmatching?

Answer 10

• Immediate-spin or computer crossmatch if no detection/history of clinically significant antibodies
• Identifies ABO compatibility
• Faster, less reagent, more efficient

Question 11

What blood is used in an emergency situation?

Answer 11

O Rh(D) -> use O Rh(D) negative in child bearing women but positive in everyone else

Question 12

What is RhD?

Answer 12

• Rhesus D = blood group protein attached to red cells
• RhD pos = 83% of population // 17% = RhD neg

Question 13

Why is RhD neg given to pregnant women?

Answer 13

RhD positive can enter maternal blood circulation -> mother makes antibodies against RhD -> maternal anti-D cross placenta destroying foetal red cells -> Haemolytic disease of newborn

Question 14

Complications of Transfusions

Answer 14

Question 15

What is Acute Haemolytic Transfusion Reaction? How common? Symptoms? Pathogenesis?

Answer 15

• 1 in 12,000
• Symptoms -> fever, chills, HTN, back pain, dyspnoea
• Pathogenesis -> intravascular haemolysis with complement activation and cytokine release