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False DUI Readings Caused by Residual Alcohol


One of the reasons many people can avoid a conviction of driving under the influence (DUI) is handheld breathalyzers. Many police officers keep these in their cars to determine a person’s blood alcohol concentration (BAC). Breathalyzers work by reading the level of alcohol in a person’s mouth and lungs when the suspect breaths into the mouthpiece. However, they aren’t the most accurate of tools.

Residual alcohol in the mouth can cause false readings on breathalyzers even when a person hasn’t had a drop to drink. This residual alcohol, also called “mouth alcohol,” can be created by a number of different products and conditions.

On the medical front, an alcoholic environment can be created in the mouth by gastroesophageal reflux disease (GERD), acid reflux, heartburn, and diabetes. Likewise, products such as chewing tobacco, mouthwashes, breath sprays, and over-the-counter medications can also contribute to mouth alcohol. Dentures and crowns can also trap foods and liquids in the mouth even long after you’ve had any food or drink.

The presence of any alcohol in the mouth doesn’t necessarily indicate you have any alcohol in the blood. Because mouth alcohol tends to dissipate after a short period of time, police officers are required to wait at least 20 minutes before administering the test. This allows any potential mouth alcohol to leave the environment of the mouth before the suspect takes the test. However, the machine must also be adequately calibrated at least once a month to be considered an accurate assessor of BAC.

If you’ve been arrested and accused of a DUI, don’t hesitate to give our Normal DUI lawyers a call. The Law Offices of Keith J. Nedwick, P.C. is dedicated to defending the rights and freedom of each of our clients. Let us see what we can do for you!

Contact us at (866) 590-8173 or fill out our online form to schedule a FREE case consultation today.

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