What term describes the percentage of alcohol in a person's blood measured by a breath testing device?

Breath Alcohol Concentration is the term that accurately describes the percentage of alcohol in a person's blood as measured by a breath testing device. This measurement represents the amount of alcohol present in a person's breath, which is then extrapolated to estimate the blood alcohol concentration (BAC).

Breath testing devices, such as breathalyzers, utilize this correlation between breath and blood alcohol levels to provide a quantifiable result, which aids law enforcement and medical professionals in assessing a person's level of intoxication. The measurement is crucial for legal and health-related purposes, as it is used to determine compliance with laws regarding driving under the influence and to evaluate an individual’s impairment level.

The other terms listed do not accurately describe this concept. Blood Alcohol Calculation is misleading, as it suggests a formula rather than a measurement; Alcohol Blood Density inaccurately implies a physical property rather than a concentration metric; and Intoxication Ratio suggests a comparison or relationship rather than a specific measurement, which does not align with the standard terminology used in breath alcohol testing.