Forced Expiratory Volume in 1 Second

**Semantic type:** Diagnostic Procedure

**Definition:** A test of lung function, the FEV1 is the volume exhaled during the first second of a forced expiratory maneuver started from the level of total lung capacity. It is the most frequently used index for assessing bronchoconstriction or bronchodilatation.

**Synonyms:** - FEV1 - FEV1 - FEV1 - FEV1%VC - Forced Expiratory Volume 1 Test - PFT/FEV1 - Pulmonary Function Test/Forced Expiratory Volume 1