Alternative Names alcohol test - breath, breathalyzer
Definition This test measures the concentration of alcohol in the blood. It does so by analyzing the level of alcohol in exhaled air.
Who is a candidate for the test? A breath alcohol test may be performed on a person who was involved in a motor vehicle accident to determine if he or she was legally intoxicated at the time of the accident.
How is the test performed? The test is administered using a kit that includes a balloon and a glass tube filled with yellow crystals. The yellow crystals turn green when exposed to alcohol-containing air.
The person being tested is asked to exhale into the balloon. The person should fill it with one continuous breath. The balloon's mouthpiece is fitted to the end of the glass tube. The air inside the balloon is allowed to flow through the glass tube for one minute. The alcohol content of the exhaled air is measured by counting the number of bands in the tube that have changed from yellow to green. This reflects the alcohol content of the blood.
A calibrated breathalyzer machine is also available to check a person's alcohol level. The person blows into a mouthpiece, and the machine displays the alcohol level. This is more accurate than the balloon type test.
What is involved in preparation for the test? There is no preparation for this test.
What do the test results mean? Normally, blood alcohol level is zero. The air a person exhales will contain no alcohol. The yellow bands in the tube will not change color.
If blood alcohol levels are elevated, some of the yellow bands in the glass tube will change from yellow to green.
If one band is green, blood alcohol levels are .00% to .05%.
If two bands are green, blood-alcohol levels are .05% to 0.1%. At these levels, the individual will suffer from reduced muscular coordination, impaired judgment, and longer reaction time due to alcohol intake.
If three bands are green, blood-alcohol levels are 0.1 to 0.15%. At these levels, a person is considered legally drunk in many states. Levels are lower in some states.
Author: Adam Brochert, MD Reviewer: Gail Hendrickson, RN, BS Last Updated: 05/17/00 Contributors Potential conflict of interest information for reviewers available on request
