A breath alcohol test (BAT) may be performed in order to determine how much alcohol is in your blood by measuring the amount of alcohol in the air you exhale. The test is known as a breath alcohol test, or a breathalyzer, and it is completely painless and noninvasive. Your doctor or a health professional will ask you to blow into a device that will instantly calculate your blood alcohol level – a number determined by the level of concentrated alcohol that travels through the lung’s air sacs (alveoli). This test may be issued if you are undergoing medical treatment or if you are getting a school or work physical. Your doctor will discuss the reason for giving you a breathalyzer and walk you through the process prior to the test.