The breath alcohol test measures the amount of alcohol in the blood by testing exhaled air. The test is performed by blowing into a breath machine 15 minutes after alcohol consumption. The test determines how much alcohol it takes to raise the blood-alcohol level to a dangerous level.
Update Date 7/22/2014
Updated by: Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.