17th February 2025

Investigations in bronchiectasis

Key investigations and findings in bronchiectasis include:

• Blood tests:
  • White cell count and CRP to rule in/out infection
  • Raised eosinophils may be suggestive of allergic bronchopulmonary aspergillosis
  • To investigate an underlying cause, e.g. rheumatoid factor, immunoglobulins, HIV test
• Sputum culture: pathogenic organisms are often found in sputum and it is advisable to send a sputum culture and sensitivity, as well as a viral and atypical screen. Pseudomonas aeruginosa is often found and can correlate with more severe lung damage. It is more likely to be antibiotic resistant than other common respiratory pathogens.
• CXR: classically shows the tram-track sign (thick-walled, dilated bronchi).
• HRCT (gold standard for diagnosis): classically shows dilated airways, with or without a thickened bronchial wall (tram-track sign) and signet-ring sign (airway appearing larger than accompanying blood vessel) (Figure 2).

• Pulmonary function tests: obstructive picture and reduced FEV1.

Image Source: Wikimedia Commons (2012). Bronquiectasia, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Bronquiectasia.jpeg#file (Accessed: 19 January 2024).