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DWI Defense Based on Challenging Breath Test

In the Twin Cities, many people charged with DWI assume they are inevitably going to lose their driver’s license and face jail time because their breath test was over the legal limit of .08 percent blood alcohol concentration (BAC). For your DWI defense, however, it is worth noting that breath testing devices do not provide infallible scientifically accurate results.

For your DWI Defense, Many Factors Should be Explored

A range of factors have been shown to compromise the reliability of a breathalyzer’s accuracy. Experienced Minnesota DWI defense lawyers at Gerald Miller, PA explore these factors to determine whether your breath test results can be challenged.

Motorists need to be aware that even if a breath testing machine recently has been calibrated and the test is administered precisely as indicated, breath test devices have an error rate (bias) of about .02 percent in either direction. This post discusses factors that can affect this error rate which increases the risk of a sober driver being convicted for DWI.

GERD/Acid Reflux/Heart Burn

The breathalyzer is designed to evaluate whether a driver is intoxicated based on the alcohol present in the air within the deep lungs. When a driver suffers from GERD, acid reflux, or heart burn, alcohol can be expelled from the stomach back up into the mouth or throat. The mouth alcohol that will be present when this happens distorts the test result because mouth alcohol that has not be metabolized by the body has a higher blood alcohol concentration (BAC) than alcohol present in the breath expelled from the deep lungs.

The impact of GERD or acid reflux on breath test results is reflected in the fact that it can impact breath test results by 400 percent. In other words, a motorist with a .04 percent BAC, which is one-half the legal limit, could produce a test result of .16 percent BAC, which is double the legal limit. This is a significant difference that could impact the driver’s DWI defense strategy.

Atkins Diet/Other Low Carb Diets

When a driver is on the Atkins diet or other low carb diets, the body often produces a compound referred to as ketones. Ketones cause the body to produce a form of alcohol referred to as isopropyl alcohol. While this form of alcohol differs from ethyl alcohol, which is present in beer, wine, and liquor, most breath testing machines cannot differentiate from these two different forms of alcohol. Further, isopropyl alcohol does not impair mental or physical driving abilities.

“Rising Blood Alcohol” DWI Defense

A good DWI defense lawyer will explain that  the timing of your consumption of alcohol can have as much impact on your breath test result as the amount of alcohol consumed. Alcohol takes up to about three hours to be completely absorbed into the blood stream. If your blood alcohol level was still rising when you were stopped by a police officer, your BAC level could be under the legal limit at the time of the stop. However, your BAC can rise above this threshold during the interim period between your being pulled over and your submitting to a formal breath test at the police station. The risk of a false positive result is highest if you have consumed alcohol shortly before driving. Although your breath test result might show that you are over the legal limit, the law makes it a crime to exceed the .08 BAC threshold while driving not when you are tested at the station.

Contamination of Test Results

A number of devices generate radio waves that are known to interfere with the circuitry in breath testing machines, such as computers, scanners, police radios, and radar guns. The presence of radio frequency interference (RFI) can result in an inaccurate test result.

Exposure to Certain Chemicals

If you work around certain chemicals and compounds, the substances might reside in your lung tissue. Substances like ethylene, nitrous oxide, isopropanol, acetonitrile, and toluene could mimic ethyl alcohol and generate a false high reading on a breathalyzer.

This is far from a comprehensive list, but the examples above demonstrates that there are many strategies for challenge breath test results. If you have been arrested for DWI, we invite you to speak to a Minnesota DWI Attorney at Gerald Miller, P.A. as soon as possible. The sooner you contact us the sooner we can start protecting your rights. Contact us today to schedule your free and confidential case evaluation.

About the author

Gerald Miller

Gerald Miller is a top-notch and experienced DWI/DUI lawyer at Gerald Miller P.A. in Minneapolis, MN. He has more than 35 years of experience in Criminal Defense practice. He has also been a mentor to numerous DUI/DWI defense attorneys.

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