Bland Altman Plot of the agreement between CEV_N2 and CEV_SF6.

<p>Healthy controls are represented by the open circles, and subjects with CF by the solid diamonds. CEV was adjusted for body size (CEV/height*100). In health there was good agreement between systems, mean difference (CEV_N2−CEV_SF6) was 0.20 (95% CI 0.017; 0.022), limits of agreement (−0.001; 0.041) with no bias observed between systems. In CF there was a strong bias such that CEV_N2 became disproportionately higher than CEV_SF6 with increasing mean values of CEV (mean difference (0.054 (95% CI 0.042; 0.067), limits of agreement (−0.041; 0.150)).