Stage	Description	Findings*
0	At risk	Risk factors and chronic symptoms but normal spirometry
I	Mild	FEV1/FVC ratio less than 70 percent
		FEV1 at least 80 percent of predicted value
		May have symptoms
II	Moderate	FEV1/FVC ratio less than 70 percent
		FEV1 50 percent to less than 80 percent of predicted value
		May have chronic symptoms
III	Severe	FEV1/FVC ratio less than 70 percent FEV1 30 percent to less than 50 percent of predicted value
		May have chronic symptoms
IV	Very severe	FEV1/FVC ratio less than 70 percent
		FEV1 less than 30 percent of predicted value
			or
		FEV1 less than 50 percent of predicted value plus severe chronic symptoms