Pulmonary function test	Normal value (95 percent confidence interval)
FEV1	80% to 120%
FVC	80% to 120%
Absolute FEV1 /FVC ratio	Within 5% of the predicted ratio
TLC	80% to 120%
FRC	75% to 120%
RV	75% to 120%
DLCO	> 60% to < 120%