what is the fef 25 75?
These include peak expiratory flow, flows at 25%, 50% and 75% of the exhaled FVC and the forced expiratory flow at 25–75% of FVC (FEF25–75%) (also called maximum mid-expiratory flow (MMEF)). ... In addition, flows at a percentage of the FVC are sensitive to measurement errors in the FVC.