Forced expiratory volume (FEV) measures how
much air a person can exhale during a forced breath. The amount of air exhaled
may be measured during the first (FEV1), second (FEV2), and/or third seconds
(FEV3) of the forced breath.
Forced vital capacity (FVC) is the total
amount of air exhaled during the FEV test.
Forced expiratory volume and forced vital capacity are lung function
tests that are measured during
spirometry. Forced expiratory volume is the most
important measurement of lung function. It is used to:
- Diagnose
chronic obstructive pulmonary disease (COPD). A person
with COPD has a lower FEV1 result than a healthy person.
- See how
well medicines used to improve breathing are working.
- Determine if
lung disease is getting worse. Decreases in the FEV1 value may indicate the
lung disease is getting worse.