The FEV1/FVC measures the amount of air exhaled in the first second of the forced vital capacity maneuver compared to the amount of air which is exhaled over the complete maneuver. The FEV1/FVC is measured in terms of the actual measured amount after 1 second versus the full measured amount. A normal FEV1/FVC is 65% (measured ratio). Please see the TDP for each Trust for the FEV1/FVC requirements of the various disease levels