Blood Alcohol Concentration or Blood Alcohol Content (BAC)

Blood alcohol concentration (BAC) is a measure of the amount of alcohol in a person's bloodstream. BAC is commonly expressed in percentage terms. For instance, having a BAC of 0.08 percent means that a person has eight parts alcohol per 10,000 parts blood in the body. State laws generally specify BAC levels in terms of grams of alcohol per 100 milliliters of blood (often abbreviated as grams per deciliter, or g/dL). BAC levels can be detected by breath, blood, or urine tests. The laws of each jurisdiction specify the preferred or required types of tests used for measurement.