What is the term used to measure the amount of alcohol in a person's bloodstream?

Blood alcohol concentration (BAC) is the term used to quantify the amount of alcohol present in a person's bloodstream. This measurement is typically expressed as a percentage, indicating the weight of alcohol per unit of blood, usually in grams per deciliter. For example, a BAC of 0.08% means there are 0.08 grams of alcohol for every 100 milliliters of blood. Measuring BAC is crucial for law enforcement and medical professionals because it helps determine an individual's level of intoxication, which can impact their ability to perform tasks safely, particularly driving.

The other terms listed, while they may sound relevant, do not accurately represent standard terminology used in medical or legal contexts. "Alcohol content level" and "Alcohol blood level" lack specific definitions and are not commonly used phrases in this context. "Drink strength index" does not correspond to any recognized measurement of blood alcohol and seems to refer more to a general idea of alcohol potency rather than a scientific measurement. Thus, blood alcohol concentration is the accurate and established term for assessing the intoxicating effects of alcohol on an individual.