. Author manuscript; available in PMC: 2017 Feb 1.

Published in final edited form as: Respir Med. 2015 Nov 11;111:30–38. doi: 10.1016/j.rmed.2015.11.004

Table 1.

Approaches to classify ventilatory impairment.

	Proposed approaches to classify ventilatory impairment		Z-scores to classify ventilatory impairment	GOLD guidelines to classify ventilatory impairment
	FEV₁ (L)	FEV₁/height² (L/m²)	FEV₁ Z-score	% Predicted FEV₁
Mild	≥2	≥0.8	>−2	≥80
Moderate	1 to 1.99	0.6 to 0.79	−2.99 to −2.0	50 to 79
Severe	0.5 to 0.99	0.4 to 0.59	−3.99 to −3.0	30 to 49
Very Severe	0 to 0.49	0 to 0.39	≤−4	0 to 29