GOLD Classification

Class	Description
0	Normal lung function	History of exposure to risk factors	Chronic symptoms
I	Mild COPD	FEV₁ / FVC < 70%	FEV₁ ≥ 80% (predicted)
II	Moderate COPD	FEV₁ / FVC < 70%	FEV₁ 50 - 79% (predicted)
III	Severe COPD	FEV₁ / FVC < 70%	FEV₁ 30 - 49% (predicted)
IV	Very severe COPD	FEV₁ / FVC < 70%	FEV₁ < 30% (predicted)	or FEV₁ < 50% (predicted) with chronic respiratory failure or right heart failure