What measurement does "Forced Expiratory Volume in 1 second" (FEV1) assess?

Forced Expiratory Volume in 1 second (FEV1) is a key measurement in pulmonary function testing that quantifies the volume of air an individual can forcefully exhale in the first second of a forced breath. This metric is critical for evaluating airflow during exhalation, providing insight into the presence and severity of obstructive airway conditions, such as asthma or chronic obstructive pulmonary disease (COPD).

By analyzing the FEV1, healthcare providers can assess how well air moves through the airways, identifying abnormalities that indicate constricted or obstructed airflow. A reduced FEV1 can indicate a significant issue with the airways, whereas a normal value may suggest the absence of obstructive pathology.

In contrast, measuring total lung capacity pertains to the total volume of air the lungs can hold, which does not directly relate to the speed or pattern of airflow during exhalation. Blood oxygen levels focus on the amount of oxygen in the bloodstream, while airway resistance relates to the opposition that airflow encounters in the respiratory system. Although these other measurements are important in assessing overall pulmonary health, they do not specifically evaluate the dynamics of forced exhalation captured by FEV1.