17th February 2025

A 35-year-old lady attends the emergency department with shortness of breath, headache, arthralgia and cough for the past two days after returning from holiday in Spain a week ago.

A 35-year-old lady attends the emergency department with shortness of breath, headache, arthralgia and cough for the past two days after returning from holiday in Spain a week ago. She has a neutrophilia on her bloods and a chest X-ray shows dense upper lobe consolidation but no effusions. Her CURB-65 score is 4. A blood culture is negative. Her past medical history includes ulcerative colitis, for which she takes mesalazine. Which further investigation is most likely to provide a diagnostic answer?

Select the SINGLE most appropriate option from the list below. Select ONE option only.