FRCPath Haem Part 1 MCQs-Transfusion 468

A 30-year-old woman (G3P1+1) at 28 weeks' gestation is referred to the fetal medicine unit with severe fetal anaemia secondary to anti-D alloimmunisation. The fetal middle cerebral artery peak systolic velocity (MCA-PSV) is 1.8 MoM, and fetal blood sampling confirms a fetal haemoglobin of 55 g/L.

An intrauterine transfusion (IUT) is planned. The consultant transfusion laboratory scientist prepares an irradiated, CMV-negative, HbS-negative, group O RhD-negative red cell unit with a haematocrit of 0.78.

During the final laboratory check, a trainee biomedical scientist asks whether the red cell unit should be resuspended in additive solution (SAGM) or remain suspended in citrate-phosphate-dextrose (CPD) before issue.

Which ONE of the following is the most appropriate recommendation?

A. The red cells should be suspended in SAGM because additive solutions improve red cell survival and reduce citrate exposure.

B. The red cells should be washed in saline before transfusion to eliminate CPD and minimise fetal hypocalcaemia.

C. The red cells should remain suspended in CPD, as this is the recommended anticoagulant/preservative solution for red cells used for intrauterine transfusion.

D. Either CPD or SAGM is equally acceptable provided the haematocrit is between 0.70 and 0.85.

E. CPDA-1 should be preferred over CPD because adenine prolongs red cell survival within the fetal circulation.