Within minutes of drinking alcohol your stomach absorbs alcohol which is then transported via your bloodstream throughout your body and causes an intoxicated affect in your brain. Blood alcohol content (BAC) is at its peak approximately sixty minutes after drinking. While a BAC of 0.08 is considered legally impaired in the US, the Department of Transportation requires employees to be stood down with a BAC of 0.02 or greater due to an increased risk of injury to self or others.
A breath alcohol test (BAT) determines the level of alcohol in the blood by measuring the air a donor exhales. A screening BAT is initially performed on a donor. If the screening test produces a positive result, the donor will undergo a confirmation test after waiting for fifteen minutes. The confirmation test and fifteen minute wait are performed to ensure that the positive result is not due to residual alcohol.