FRCPath Haem Part 1 MCQs-Transfusion 510
A 45-year-old patient with acute myeloid leukaemia is undergoing an allogeneic haematopoietic stem cell transplant (allo-HSCT).
Donor ABO group: B
Recipient ABO group: A
The patient is currently in the pre-engraftment phase (Phase II).
The patient develops significant bleeding associated with coagulopathy and requires fresh frozen plasma (FFP).
According to NHSBT guideline which ABO group of FFP should be selected?
Select ONE best answer.
A. Group A FFP
B. Group B FFP
C. Group AB FFP
D. Group O FFP
E. Either group A or B FFP, provided it is high-titre negative
Correct Answer: C. Group AB FFP
This is a bidirectional mismatch
There are two incompatibilities:
Major mismatch: recipient anti-B can react with donor-derived B red cells.
Minor mismatch: donor anti-A can react with residual recipient A red cells.
Therefore, this is a bidirectional (major plus minor) ABO incompatibility.
2. Why is AB plasma preferred?
Group AB plasma contains neither anti-A nor anti-B antibodies.
Consequently:
It will not attack recipient group A red cells.
It will not attack donor-derived group B red cells.
This makes group AB plasma the appropriate choice during the pre-engraftment phase.
3. Important FRCPath learning point
Do not confuse routine FFP compatibility with ABO-incompatible HSCT transfusion support.
In routine transfusion, group A recipients generally receive group A…