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Common Mistakes in Preliminary Breath Testing for Alcohol

New Hampshire law prohibits driving a motor vehicle with a blood alcohol concentration (BAC) of 0.08 percent or above. A driver whose BAC is higher than the legal limit may face conviction for driving under the influence (DUI).

BAC readings are often taken before a person is arrested, using a preliminary breath testing (PBT) machine. Since the PBT machine produces a number that can easily be compared to the legal limit number, it’s tempting for police officers and prosecutors to build an entire case against a driver based on the reading the machine gives. However, these cases may be built on an illusion if the PBT machine failed to give an accurate BAC reading.

A BAC reading based on a breath sample can only be as accurate as the PBT machine that examines the sample. All brands of breath testing machines need regular maintenance to ensure they work properly. They must also be calibrated according to a strict schedule set by the manufacturer. If a PBT machine has not been maintained and calibrated correctly, its results cannot be trusted.

Also, the officer giving the breath test must do it properly in order to get trustworthy results. An officer who tests someone who has just used mouthwash, breath spray, or another alcohol-containing product may get a falsely high BAC reading. The officer must also explain that the driver needs to blow into the tube for long enough for the machine to get a full sample, and must ensure that the driver follows these instructions. An incomplete sample may also give a false BAC reading.

If you’ve been charged with a DUI in New Hampshire as the result of a Preliminary Breath Test, please don’t hesitate to contact the experienced NH DUI defense attorneys at Tenn And Tenn, P.A. We can help you fight for the best possible outcome in your case. To learn more, call us today at 1-603-624-3700 for a free telephone consultation, or call our Free Helpline at 1-888-511-1010.