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Breaking down breathalyzer accuracy


Those in Carle Place who have been arrested for driving under the influence of alcohol may feel it pointless to dispute the charges against them. Typically, such an arrest only happens if law enforcement officials have some sort of proof to back up their suspicions. In most cases, that proof comes in the form of a blood-alcohol measurement taken using a handheld breath testing device. Yet are such instruments accurate enough on their own to prove one was indeed intoxicated?

According to information shared by the National Motorists Association, the answer to that question is no. In fact, their research shows that handheld breath testing devices may have a margin of error as great as 50 percent. When considering the implications that can come with a DUI conviction (e.g. a license suspension, heavy fines), it may seem downright frightening that such charges are supported by evidence deemed to be that unreliable.

Yet exactly what is it that contributes to such a wide margin of error? Knowing this requires understanding the assumptions made handheld breath testing devices themselves. When one ingests alcohol, it makes its way into their bloodstream and eventually is pumped into their lungs. Once there, it comes in contact with oxygen, which causes a portion of it to vaporize into a gas that is then exhaled when the person breaths (this is how breath is determined to offer a measurement of one’s BAC).

The amount of alcohol on one’s breath is directly proportional to that in their blood. According to the Alcohol Pharmacology Education Partnership, breath testing devices assume that ratio to be 2100:1. In reality, however, it can be as varied as 1500 to 3000:1. Each subject presents a different ratio, and thus a different opportunity to generate a measurement error.