Blood Alcohol Concentration, or BAC, is the measurement of what?

• A. The amount of alcohol in the bloodstream
• B. The percentage of fat in the blood
• C. The rate at which alcohol is metabolized
• D. The legal limit for driving

Answer: (A)

Blood Alcohol Concentration measures how much ethanol is present in the blood at a given moment, i.e., the concentration of alcohol in the bloodstream. It’s usually expressed as a percentage (often interpreted as grams of alcohol per deciliter of blood). This concentration grows with more drinking and is influenced by factors like body weight, sex, and whether you’ve eaten. It’s used to assess impairment and enforce drinking-and-driving laws. The other ideas don’t fit because BAC is not about the fat content in blood, nor is it the rate at which alcohol is metabolized, and while legal limits exist, they’re based on a BAC value, not what BAC itself measures.