30th April 2024

A 60-year-old male, with a history of splenectomy following a car accident five years ago, presents with recurrent infections and mild fatigue.

A 60-year-old male, with a history of splenectomy following a car accident five years ago, presents with recurrent infections and mild fatigue. He reports frequent episodes of cold and flu-like symptoms over the past year. His vaccinations are up to date, including those recommended for asplenic patients. On examination, he appears slightly pale but is otherwise unremarkable. No lymphadenopathy or hepatomegaly is noted.

Which investigation is most likely to reveal the underlying cause of his recurrent infections?