Clinical meaning
COPD diagnosis requires post-bronchodilator spirometry demonstrating a fixed ratio of FEV1/FVC < 0.70. Unlike asthma, airflow limitation in COPD is not fully reversible. GOLD severity staging uses post-bronchodilator FEV1 percent predicted: GOLD 1 (mild) >= 80%, GOLD 2 (moderate) 50-79%, GOLD 3 (severe) 30-49%, GOLD 4 (very severe) < 30%. The 2024 GOLD ABE assessment combines symptom burden (mMRC or CAT score) with exacerbation history: Group A (low symptoms, low exacerbation risk), Group B (high symptoms, low exacerbation risk), Group E (any exacerbation history). This replaces the previous ABCD tool. COPD phenotyping (emphysema-predominant vs chronic bronchitis-predominant vs asthma-COPD overlap) guides therapy selection. Blood eosinophils are a key biomarker: >= 300 cells/mcL predicts ICS benefit while < 100 cells/mcL predicts increased pneumonia risk with ICS.
Diagnosis & workup
Diagnostics & workup: - Post-bronchodilator spirometry: FEV1/FVC < 0.70 (mandatory for diagnosis) - GOLD staging by FEV1 % predicted after bronchodilator - mMRC dyspnea scale or CAT score for symptom assessment - Alpha-1 antitrypsin level (serum; if low, confirm with phenotype/genotype) - CBC with differential for eosinophil count (guides ICS decision) - CT chest for emphysema characterization and lung cancer screening eligibility