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

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 ¹.

Key investigations recommended to assess for COPD include:

• Spirometry: Post-bronchodilator spirometry should be performed to confirm the diagnosis of COPD ¹. Spirometry is performed at diagnosis, to reconsider the diagnosis for people with an exceptionally good response to treatment, and to monitor disease progression ¹.
• Chest Radiograph: A chest radiograph should be obtained at the time of initial diagnostic evaluation to exclude other pathologies ¹.
• Full Blood Count (FBC): An FBC should be performed to identify anaemia or polycythaemia ¹.
• Body Mass Index (BMI) Calculation: BMI should be calculated as part of the initial diagnostic evaluation ¹.

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 ¹.
• Serial Home Peak Flow Measurements: These can be used to help exclude asthma if diagnostic doubt remains ¹.
• ECG and Serum Natriuretic Peptides: These assess cardiac status if cardiac disease or pulmonary hypertension are suspected ¹.
• Echocardiogram: This also assesses cardiac status if cardiac disease or pulmonary hypertension are suspected ¹.
• 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 ¹.
• 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 ¹.
• Transfer Factor for Carbon Monoxide (TLCO): This investigates symptoms disproportionate to spirometric impairment or assesses suitability for lung volume reduction procedures ¹.