investigations in COPD

Last edited 06/2020

The investigations for COPD include:

• spirometry
  • is the most reproducible and objective measurement of airflow limitation
• should be performed at the time of diagnosis and to reconsider the diagnosis, if patients show an exceptionally good response to treatment
• a decrease in both FEV1 and FVC is seen in COPD
• measurements are evaluated by comparison with reference values based on age, height, sex and race
• spirometry should be used to monitor disease progression (1)

• a chest radiograph to exclude other pathologies
• the full blood count - to identify anaemia or polycythaemia
• body mass index (BMI) calculated

Additional investigations which may be useful according to the clinical findings include:

• serial domiciliary peak flow measurements – to exclude asthma if diagnostic doubt remains
• alpha-1 antitrypsin - indicated if early onset, minimal smoking history or family history
• transfer factor for carbon monoxide (TLCO) - to investigate symptoms that seem disproportionate to the spirometric impairment
• pulse oximetry - to assess need for oxygen therapy if cyanosis, or cor pulmonale present, or if FEV1 < 50% predicted
• CT scan of the thorax
• to investigate symptoms that seem disproportionate to the spirometric impairment
• to investigate abnormalities seen on a chest radiograph
• to assess suitability for surgery
• be aware that the presence of emphysema on a CT scan is an independent risk factor for lung cancer (1)
• the ECG may show cor pulmonale:
• tall P waves
• right bundle branch block
• right ventricular hypertrophy
• for more information regarding the ECG changes in COPD then click here
• echocardiogram - to assess cardiac status if features of cor pulmonale
• arterial blood gases:
• pink puffer - near-normal gases
• blue bloater - hypercapnia, hypoxaemia, severe nocturnal hypoxaemia, elevated bicarbonate

• sputum culture – to identify organisms if sputum is persistently present and purulent (1,2)

Reference:

• (1) National Institute for Health and Clinical Excellence (NICE) 2018. Chronic obstructive pulmonary disease: Management of chronic obstructive pulmonary disease in adults in primary and secondary care
• (2) Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2018. Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease.