17th February 2025

A 20-year-old lady presents to the respiratory clinic with chronic recurrent chest infections and a productive cough with yellow or green sputum daily for the last few years.

A 20-year-old lady presents to the respiratory clinic with chronic recurrent chest infections and a productive cough with yellow or green sputum daily for the last few years. She has been treated by her GP with multiple courses of antibiotics, which do help for a short time but never completely clear her symptoms. She has also noted difficulty gaining weight and is of short stature. On examination, she has finger clubbing, appears to have a low BMI and has bilateral coarse chest crackles. 

What investigation would be diagnostic?

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