FEV1

FEV1, or forced expiratory volume in one second, is the amount of air you can forcefully blow out in the first second of a hard exhale. It is measured during a breathing test called spirometry. Doctors use it to gauge how well the lungs move air and whether airflow is obstructed or restricted.

Origin

The measurement grew out of spirometry, a technique pioneered by John Hutchinson in the 1840s. Standardized FEV1 testing became routine in twentieth-century pulmonary medicine and occupational health screening.

Significance in Asbestos Context

For someone with asbestos disease, FEV1 is part of the pulmonary function testing that documents how much lung capacity has been lost. Asbestosis and pleural disease typically cause a restrictive pattern, where both FEV1 and total lung volume fall together, rather than the obstructive pattern seen in smoking-related COPD. These numbers appear in medical records and can support both diagnosis and the measure of impairment in a claim. Because the test depends on effort, results are usually repeated. If you smoked, doctors look at the overall pattern to separate asbestos-related restriction from smoking-related obstruction.

Example Sentence

His FEV1 had dropped to 62 percent of predicted, consistent with the restrictive impairment expected in asbestosis.

Related Terms

Spirometry, Pulmonary Function Test, FVC, Restrictive Lung Disease, Diffusing Capacity

Notes

• Ask for your full pulmonary function report, not just the FEV1; the FEV1/FVC ratio distinguishes restriction from obstruction.
• Keep copies of serial tests, since a declining trend documents progression and impairment.
• Give full effort and follow the technician's coaching, because low effort can understate or distort results.