What investigations are recommended for a patient with chronic bronchitis to assess for COPD?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 14 August 2025Updated: 14 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

For a patient with chronic bronchitis, which is a symptom that can indicate chronic obstructive pulmonary disease (COPD), the diagnosis of COPD is suspected based on symptoms and signs, and supported by spirometry .

Key investigations recommended to assess for COPD include:

  • Spirometry: Post-bronchodilator spirometry should be performed to confirm the diagnosis of COPD . Spirometry is performed at diagnosis, to reconsider the diagnosis for people with an exceptionally good response to treatment, and to monitor disease progression .
  • Chest Radiograph: A chest radiograph should be obtained at the time of initial diagnostic evaluation to exclude other pathologies .
  • Full Blood Count (FBC): An FBC should be performed to identify anaemia or polycythaemia .
  • Body Mass Index (BMI) Calculation: BMI should be calculated as part of the initial diagnostic evaluation .

Additional investigations may be performed when needed, based on clinical findings:

  • Sputum Culture: This is used to identify organisms if sputum is persistently present and purulent .
  • Serial Home Peak Flow Measurements: These can be used to help exclude asthma if diagnostic doubt remains .
  • ECG and Serum Natriuretic Peptides: These assess cardiac status if cardiac disease or pulmonary hypertension are suspected .
  • Echocardiogram: This also assesses cardiac status if cardiac disease or pulmonary hypertension are suspected .
  • CT Scan of the Thorax: A CT scan may be used to investigate symptoms disproportionate to spirometric impairment, signs suggesting another lung diagnosis (such as fibrosis or bronchiectasis), abnormalities on a chest X-ray, or to assess suitability for lung volume reduction procedures .
  • Serum Alpha-1 Antitrypsin: This is assessed for alpha-1 antitrypsin deficiency if there is early onset COPD, a minimal smoking history, or a family history .
  • Transfer Factor for Carbon Monoxide (TLCO): This investigates symptoms disproportionate to spirometric impairment or assesses suitability for lung volume reduction procedures .

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