Two hours after a transfusion of four units of packed red cells, a patient develops dyspnoea with bilateral radiographic infiltrates. Which single test best distinguishes transfusion-associated circulatory overload from TRALI?

• A Serum tryptase level
• B Peripheral blood eosinophil count
• C Direct antiglobulin (Coombs) test
• D Serum B-type natriuretic peptide ✓

Explanation

TACO produces hydrostatic pulmonary oedema from circulatory volume overload, so it raises B-type natriuretic peptide, whereas TRALI is non-cardiogenic oedema with a normal BNP. This single measurement separates the two conditions when the radiographs look similar. The Coombs test relates to haemolysis, tryptase to anaphylaxis, and neither helps distinguish these two pulmonary syndromes.

Reference: Sabiston Textbook of Surgery, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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