Forced Expiratory Volume and Forced Vital Capacity

Topic Overview

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 obstructive lung diseases such as asthma and chronic obstructive pulmonary disease (COPD). A person who has asthma or COPD has a lower FEV1 result than a healthy person.
  • See how well medicines used to improve breathing are working.
  • Check if lung disease is getting worse. Decreases in the FEV1 value may mean the lung disease is getting worse.

Related Information

Credits

ByHealthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Anne C. Poinier, MD - Internal Medicine
Adam Husney, MD - Family Medicine
Specialist Medical Reviewer Robert L. Cowie, MB, ChB, MD, MSc, FCP(SA), MFOM - Pulmonology
Elizabeth T. Russo, MD - Internal Medicine

Current as ofDecember 6, 2017

Is it an emergency?

If you or someone in your care has chest pains, difficulty breathing, or severe bleeding, it could be a life-threatening emergency. Call 9-1-1 or the local emergency number immediately.
If you are concerned about a possible poisoning or exposure to a toxic substance, call Poison Control now at 1-800-567-8911.

Thanks to our partners and endorsers: