The period after alcohol is consumed but before the body reaches its highest blood alcohol concentration.

"After alcohol is consumed" matters because absorption starts in the stomach and small intestine, not at the moment of drinking alone. Food in the stomach, drink strength, body size, and how quickly alcohol is consumed all affect how fast alcohol enters the bloodstream. "Before the body reaches its highest blood alcohol concentration" means BAC is still rising during this phase. A person can test lower at one moment and higher a short time later, even without another drink. Once absorption is complete, the body moves into the post-absorptive or elimination phase, when BAC generally begins to fall at a more predictable rate.

In a DUI case, the absorptive phase can affect whether a chemical test accurately reflects impairment at the time of driving. That issue often appears in retrograde extrapolation, where the State or a defense expert estimates an earlier BAC from a later test result. If the driver was still absorbing alcohol, that estimate becomes less certain because BAC may not yet have peaked.

In North Carolina, a BAC of 0.08 or more supports an implied-consent DWI charge under N.C. Gen. Stat. § 20-138.1 (2024). The absorptive phase may be relevant when the breath or blood test was taken well after the stop, crash, or arrest, especially if recent drinking, food intake, or the timing of the last drink is disputed.