ABSTRACT
Traditionally, COPD severity was measured by forced expiratory volume in one second (FEV1) percentage predicted values. FEV1 percentage predicted values are accurate and easy to measure. NICE has classified three levels of severity which are now commonly used internationally (see Table 7.1). Forced expiratory volume in 1 second (FEV<sub>1</sub>) (NICE guidelines)
Copd Severity
Fev1 (% Predicted Value)
Mild
50–80%
Moderate
30–49%
Severe
< 30%
