From the Guidelines
The diagnosis of Chronic Obstructive Pulmonary Disease (COPD) should be considered in individuals with chronic respiratory symptoms and/or exposure to risk factors, and confirmed by a post-bronchodilator FEV1/FVC ratio less than 0.7, as recommended by the GOLD Science Committee in 2025 1. To diagnose COPD, the following criteria should be met:
- Symptoms such as chronic cough, sputum production, dyspnea, or history of exposure to risk factors like tobacco smoke, occupational dusts, or indoor air pollution
- Spirometry testing showing airflow limitation that is not fully reversible, with a post-bronchodilator FEV1/FVC ratio less than 0.7
- The severity of COPD can be classified based on the FEV1 percentage of predicted value: mild (≥80%), moderate (50-79%), severe (30-49%), or very severe (<30%) The GOLD assessment also incorporates symptom burden using validated questionnaires like the COPD Assessment Test (CAT) or Modified Medical Research Council (mMRC) dyspnea scale, along with exacerbation history to guide treatment decisions 1. It is essential to note that chest imaging is not required for diagnosis but may help identify emphysema, bullae, or rule out alternative diagnoses, and alpha-1 antitrypsin deficiency testing should be considered, especially in younger patients or those with minimal smoking history. The use of pre- and post-bronchodilator spirometry is crucial in diagnosing COPD, and the GOLD Science Committee recommends using pre-BD spirometry to rule out COPD and post-BD measurements to confirm the diagnosis, which will reduce clinical workload and limit COPD overdiagnosis 1.
From the Research
Diagnostic Criteria for COPD
The diagnostic criteria for Chronic Obstructive Pulmonary Disease (COPD) involve a combination of clinical assessment, symptoms, and pulmonary function tests. The key criteria include:
- A history of respiratory symptoms such as wheezing, cough, phlegm, and breathlessness on exertion 2
- Physical examination findings, although limited, may include auscultated pulmonary wheezing or reduced breath sounds 2
- Spirometric airflow obstruction after bronchodilation, defined as a lowered ratio of the forced volume in one second to the forced vital capacity (FEV1/FVC ratio) 2, 3, 4
Spirometry and FEV1/FVC Ratio
Spirometry is a crucial diagnostic tool for COPD, and the FEV1/FVC ratio is used to assess airflow obstruction. Different thresholds are recommended to define a low FEV1/FVC ratio, including a fixed threshold and one varying with gender and age 2. The Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria suggest a post-bronchodilator FEV1/FVC ratio of < 70% to confirm the diagnosis of COPD 5.
Additional Diagnostic Tests
Additional lung function tests, such as body plethysmography, may be necessary to assess pulmonary function and exclude alternative diagnoses 2, 4. Chest radiography has no diagnostic value for COPD but can be useful in excluding other conditions such as heart failure or lung cancer 2.
Severity Classification
The severity of COPD can be classified using the FEV1% predicted (ppFEV1) or the FEV1/FVC ratio. A new severity classification scheme, called STaging of Airflow obstruction by Ratio (STAR), has been proposed, which uses the FEV1/FVC ratio to categorize the severity of airflow obstruction 6. This scheme has been shown to provide better discrimination between the absence of airflow obstruction and stage 1 COPD, as well as between different stages of disease severity.
Differential Diagnosis
Distinguishing between COPD and asthma can be challenging, and the current recommended spirometric indices may not be optimal for differentiating between the two conditions 5. A combination of post-bronchodilator FEV1 < 80% of the predicted value and a post-bronchodilator FEV1/FVC ratio of < 70% has been suggested, but this criteria has limited specificity 5.