Challenging the validity of breath test results

On Behalf of | Feb 5, 2021 | dui defense |

Those arrested for allegedly driving while intoxicated in Georgia based primarily on the results generated by a hand-held breath testing device may rightly question how breath test results indicate the alcohol content of their blood. Understanding why requires that one comprehends the pathway ethanol alcohol (the type of alcohol used in beverages) takes from ingestion to expiration.

Yet as one researches this topic, they may begin to see issues with the way hand-held breath testing devices work that many may see as problematic. This may add credence to one’s challenge of the breath test results law enforcement officials try to use as evidence against them.

Breath-test margin of error

According to the National Motorists Association, many experts estimate that hand-held breath testing devices may have a margin of error as high as 50%. This extreme potential for error seemingly undercuts their validity. Indeed, such results should only serve as probable cause to detain one on the suspicion of drunk driving. Minus a subsequent chemical breath test indicating one’s intoxication, one might argue that little reputable evidence exists to warrant a criminal charge.

A breakdown of breath-test device mechanics

How is it that hand-held breath testing devices can have such a high margin of error? These devices measure the alcohol content on one’s breath to infer the concentration in their blood (due to ethanol alcohol entering the bloodstream by permeating the lining of the organs of one’s gastrointestinal tract through passive diffusion). A portion of that alcohol vaporizes in the lungs and leaves one’s body when they breathe. Breath testing devices generate measurements by assuming a constant blood-to-breath alcohol ratio of 2100:1. Per the Alcohol Pharmacology Education Partnership, however, one’s actual blood-to-breath ratio may range between 1500:1 to 3000:1 based on an array of factors such as age, gender and genetic makeup.