Table 1: GOLD Staging Criteria for COPD^*.

Stage	Severity	FEV1/FVC	FEV1	Symptoms
I	Mild	< 0.70	FEV1 ≥ 80% predicted	Symptoms may or may not be present Possible symptoms include chronic cough and sputum production
II	Moderate	< 0.70	50% ≤ FEV1 < 80% predicted	Shortness of breath on exertion Cough and sputum production are sometimes present
III	Severe	< 0.70	30% ≤ FEV1 < 50% predicted	Greater shortness of breath, reduced exercise capacity, fatigue, and repeated exacerbations
IV	Very severe	< 0.70	FEV1 < 30% predicted or FEV1 < 50% predicted plus chronic respiratory failure	Respiratory failure, which may also lead to cor pulmonale

^*Abbreviations: COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease.

Source: Global Initiative for Chronic Obstructive Lung Disease, 2010. (1)