Table 1. Spirometric Classification of COPD Severity Based on Post-Bronchodilator FEV1.

GOLD Stage	Spirometry Criteria
Stage I	FEV1/FVC <0.7 and FEV1 ≥80% predicted
Stage II	FEV1/FVC <0.7 and 50% ≤ FEV1 <80%
Stage III	FEV1/FVC <0.7 and 30% ≤ FEV1 <50%
Stage IV	FEV1/FVC <0.7 and FEV1 <30%