What lung function tests are recommended for patients with bronchiectasis?

Recommended Lung Function Tests for Bronchiectasis

According to standard guidelines, patients with bronchiectasis should undergo regular lung function monitoring including spirometry (FEV1 and FVC), sputum culture, and pulse oximetry as the core recommended tests. 1, 2

Core Lung Function Tests for Bronchiectasis

Initial Assessment

• Spirometry:

  • Measures FEV1 and FVC to establish baseline lung function 1, 2
  • Helps identify obstructive, restrictive, or mixed patterns 2
  • Essential for calculating severity scores like the Bronchiectasis Severity Index (BSI) 1

• Sputum Collection:

  • For routine bacterial culture 1
  • For mycobacterial culture 1
  • Essential for pathogen identification and guiding antibiotic therapy 2

• Pulse Oximetry:

  • Screens for respiratory failure 1, 2
  • Non-invasive assessment of oxygen saturation 2

Routine Monitoring Tests

The British Thoracic Society recommends the following schedule for routine monitoring based on disease severity 1:

Test	Mild Disease	Moderate-Severe Disease
BMI (Body Mass Index)	Annual	Annual
Exacerbation History	Annual	6 monthly
Sputum Culture	Annual	6 monthly
MRC Dyspnoea Score	Annual	6 monthly
Spirometry	Annual	Annual
Oxygen saturation monitoring	Annual	6 monthly

Additional Testing Based on Clinical Context

For Deteriorating Patients

• More frequent spirometry to track lung function decline 1
• Additional sputum cultures to identify new pathogens or antibiotic resistance 1
• Assessment for comorbidities that may be contributing to deterioration 1

Advanced Lung Function Testing

• Body plethysmography:

  • Measures residual volume (RV) and total lung capacity (TLC)
  • Particularly useful for detecting air trapping (present in 70% of patients) 3
  • More sensitive than standard spirometry in detecting functional abnormalities 3

• Diffusing Capacity (DLCO):

  • Impaired in approximately 56% of bronchiectasis patients 3
  • Helps assess gas exchange capability 2

• Lung Clearance Index (LCI):

  • More sensitive than FEV1 in detecting abnormalities shown on CT scans 4
  • Abnormal in 88% of patients compared to 62% with abnormal FEV1 4
  • Highly repeatable (intraclass correlation coefficient of 0.94) 4

Imaging

• CT scan:
  • Gold standard for diagnosis 2
  • Repeat CT scans should be individualized based on clinical need 1
  • Consider repeating only when results would change management 1, 2

Clinical Pearls and Pitfalls

• Air trapping and diffusion impairment are actually more common functional abnormalities than airflow obstruction in bronchiectasis 3

• Pitfall: Relying solely on spirometry may miss significant functional abnormalities. Consider more comprehensive testing in patients with symptoms disproportionate to spirometry findings 3

• Pitfall: Upper airway swabs are unreliable for predicting lower airway pathogens. Always obtain sputum samples when possible 1

• Pearl: Bronchial reversibility testing should assess both FEV1 and residual volume, as RV reversibility (17.6%) is more common than FEV1 reversibility (4.3%) 3

• Pearl: A baseline chest X-ray provides a useful comparator for future clinical deterioration 1

By implementing these recommended lung function tests according to established guidelines, clinicians can better monitor disease progression, detect complications early, and optimize treatment strategies for patients with bronchiectasis.