What Can Cause a False Positive on a DUI Breath Test?

When law enforcement in North Carolina pulls over a driver due to suspicion of DWI, police officers may attempt to determine if a driver is intoxicated by administering a breathalyzer test to measure the driver’s blood alcohol concentration (BAC) in his/her bloodstream. If a breath test comes back positive, the result is enough probable cause to make an arrest.

However, there are many instances where a breathalyzer test produces unreliable results. So, if you’re not under the influence of alcohol, it is possible the breath test indicates that you are, resulting in an arrest.

The following are the common factors which can lead to a false positive on a DWI breath test:

  • The breathalyzer wasn’t properly calibrated – Police officers are required to use federally-approved breathalyzer devices and recalibrate them each time after use. In addition, they must maintain accurate and detailed records when it comes to maintenance. If these requirements are not met, then an uncalibrated device could produce inaccurate results.
  • The police officer failed to wait at least 15 minutes before administering the breath test – Prior to administering the test, officers are required to observe the driver—known as the observation period—for at least 15 minutes to ensure the suspect doesn’t consume any foods or liquids, vomit, burp, or smoke prior to collecting the breath sample. Failing to perform the observation period can result in accurate testing.
  • The police officer lacked formal training to administer breath test – Officers must follow a specific protocol when administering breathalyzer tests. If law enforcement skips a step in the process, or fails to consider certain factors—such as the driver’s medical conditions and the conditions of the testing area—then the driver can argue that the officer failed to administer the test properly.
  • The driver has certain health conditions – Medical conditions can significantly affect the accuracy of breath tests. For example, those with diabetes have higher levels of ketones in their bloodstream, which can be falsely identified as ethyl alcohol, thus having an impact on breathalyzers. People with acid reflux or GERD can also obtain falsely high results due to the acid in their mouth.
  • The driver consumed something other than alcohol – Common items such as mouthwash, cough syrup, and breath mints can make breath test indicate the presence of alcohol in your bloodstream.

If you believe the results of the breathalyzer test are inaccurate, an experienced criminal defense attorney can prove it in court by creating a strong defense strategy. If the results are, in fact, inaccurate, then they could be inadmissible in court, which could lead to the dismissal of your entire case.

For more information about DWI arrests in Raleigh, NC, contact Sandman, Finn & Fitzhugh today.


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