Assess symptoms: chronic cough, sputum production, dyspnea, wheeze, recurrent respiratory infections
Review risk factors: smoking, biomass exposure, occupational dusts or chemicals, air pollution, alpha-1 antitrypsin deficiency, family history
Perform physical examination: prolonged expiration, wheezing, decreased breath sounds, barrel chest, use of accessory muscles, cyanosis, signs of cor pulmonale
Confirm with spirometry after bronchodilator
Diagnose airflow obstruction if post-bronchodilator FEV1/FVC is less than 0.70
Assess severity with FEV1 percent predicted
Consider full pulmonary function tests if diagnosis is uncertain
Obtain chest X-ray to exclude other conditions
Consider chest CT if needed for emphysema, alternative diagnoses, or complications
Check oxygen saturation with pulse oximetry
Obtain arterial blood gas if severe disease or hypoxemia is suspected
Evaluate for alpha-1 antitrypsin deficiency in younger patients or those with minimal smoking history
Exclude asthma, heart failure, bronchiectasis, interstitial lung disease, and tuberculosis
Assess exacerbation history and symptom burden using validated tools such as CAT or mMRC
Consider laboratory tests as indicated, including CBC and eosinophil count
Refer to a specialist if diagnosis is uncertain or disease is severe