What does a higher alcohol concentration in blood generally imply about breath alcohol concentration (BrAC)?

A higher alcohol concentration in blood generally implies that the breath alcohol concentration (BrAC) will be proportionally higher due to the relationship between the two measures. The body metabolizes alcohol in a fairly consistent ratio, resulting in a predictable correlation between blood alcohol content (BAC) and BrAC.

Specifically, law enforcement uses the Widmark formula to estimate this relationship, which indicates that for every unit of alcohol in the bloodstream, there is a corresponding amount of alcohol in the breath. As a result, when someone has a higher concentration of alcohol in their blood, it is logical to deduce that their breath will also reflect this increased level — hence the BrAC will be proportionally higher.

This relationship is rooted in how alcohol distributes throughout the body. When a person consumes alcohol, it enters the bloodstream and eventually reaches the lungs, where it is expelled in breath exhalation. Therefore, it would be expected that a rise in blood alcohol levels would result in a corresponding rise in alcohol detected in breath samples.