Blood alcohol concentration measures what?

Blood alcohol concentration (BAC) is defined as the amount of alcohol present in a person's bloodstream and is specifically measured as grams of alcohol per 100 milliliters of blood. This numerical value provides an objective metric that law enforcement and medical professionals use to assess an individual's level of intoxication. The BAC level can indicate impairment and is critical in both legal situations and public safety considerations.

Understanding BAC is important because it directly correlates with physical and cognitive impairment levels. For example, a BAC of 0.08% is often the legal limit for driving in many jurisdictions, signifying that any level above this is associated with increased risk of accidents and impaired functioning. This measurement does not just reflect the number of drinks consumed but rather the precise concentration of alcohol in the bloodstream, taking into account individual factors such as body weight, gender, metabolism, and time since drinking.