Which statement correctly describes FEV1?

Which statement correctly describes FEV1?

• A. Forced expiratory volume in 2 seconds; airflow obstruction measure.
• B. Forced expiratory volume in 1 second; airflow obstruction measure.
• C. Forced expiratory volume in 1 second; total lung capacity.
• D. Forced expiratory capacity; airway flow.

Answer: (B)

FEV1 is the amount of air you can forcefully exhale in the first second of a forced breath, measured during spirometry. This makes it a key indicator of airway obstruction because obstructed airways slow the initial burst of exhalation, reducing the volume expelled in the first second. The statement that best describes FEV1, therefore, is that it is the forced expiratory volume in 1 second and serves as a measure of airway obstruction. The other descriptions miss the mark: measuring over two seconds would be a different metric (FEV2, not FEV1); total lung capacity refers to a different parameter (TLC); and calling it “forced expiratory capacity” or focusing on “airway flow” isn’t the standard definition—FEV1 is specifically a volume exhaled in the first second. In practice, FEV1 is often interpreted together with FVC to assess obstruction via the FEV1/FVC ratio.

FEV1 is the amount of air you can forcefully exhale in the first second of a forced breath, measured during spirometry. This makes it a key indicator of airway obstruction because obstructed airways slow the initial burst of exhalation, reducing the volume expelled in the first second. The statement that best describes FEV1, therefore, is that it is the forced expiratory volume in 1 second and serves as a measure of airway obstruction.

The other descriptions miss the mark: measuring over two seconds would be a different metric (FEV2, not FEV1); total lung capacity refers to a different parameter (TLC); and calling it “forced expiratory capacity” or focusing on “airway flow” isn’t the standard definition—FEV1 is specifically a volume exhaled in the first second. In practice, FEV1 is often interpreted together with FVC to assess obstruction via the FEV1/FVC ratio.