FRCPath Haem Part 1 MCQs-Gen Haem 490

A 68-year-old man is admitted with community-acquired pneumonia. His Hb is 82 g/L, WBC 14.2 × 10⁹/L and platelets 285 × 10⁹/L. Blood film shows red cell agglutination. The MCV is reported as 118 fL, but a repeat sample after warming to 37°C gives an MCV of 91 fL.

DAT is:

• IgG: negative

• C3d: strongly positive

An antibody screen performed at room temperature is positive with all screening cells, but testing at 37°C using the indirect antiglobulin technique is negative. The patient's plasma reacts strongly with adult O cells at 4°. Autocontrol is positive at 4°C.

He requires a red cell transfusion because of symptomatic anaemia.

Which of the following is the MOST appropriate interpretation and transfusion strategy?

A. Warm autoimmune haemolytic anaemia due to an IgG panagglutinin; transfuse least-incompatible ABO-compatible red cells and commence corticosteroids

B. Cold autoimmune haemolytic anaemia due to anti-I; keep the patient and blood warm and transfuse ABO-compatible red cells through a blood warmer

C. Cold autoimmune haemolytic anaemia due to anti-i; transfuse only group O red cells after selecting units negative for the i antigen

D. Paroxysmal cold haemoglobinuria due to a biphasic anti-P; perform a Donath–Landsteiner test and avoid transfusion unless life-threatening

E. Cold alloantibody caused by recent transfusion; provide antigen-negative red cells based on the antibody screen and no special warming is required