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FL DUI GROUP Florida DUI Defense Attorney
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Can a Breath Test for DUI Give a False Positive?


A false positive occurs when a blood or breath test shows that someone’s blood alcohol content (BAC) is above the legal limit when it isn’t. If you are not drunk, then you should not bear the costs related to a DUI. However, a false positive on a breathalyzer test could complicate the matter. You could find yourself facing charges when you were below the .08 threshold for legal drunkenness.

A breath test is among the most accurate ways to determine a driver’s BAC. But it can also result in false positives. In this article, the Florida DUI defense attorneys at FL DUI Group will discuss false positives in breathalyzer and blood tests.

What is a PBT/breath test? 

A preliminary breath test or PBT is designed to detect alcohol in your system through your breath. It works by absorbing alcohol through your breath and then rendering a reading based on the amount of alcohol. In Florida, it is illegal to operate a motor vehicle with a BAC of .08 or higher.

An officer may require you to blow into a PBT using a hand-held device known as a breathalyzer. If the breathalyzer renders a reading of .08 or higher, it can be used to declare you legally drunk. It can also be used to gather further testing or make an arrest.

False positives and breathalyzer tests 

Breathalyzer tests are generally accurate, but can occasionally result in false positives. One potential reason for a false positive may be that you still have some alcohol in your mouth from the last drink you took. In this case, the breathalyzer may render a result that is higher than your actual BAC. Also, those who recently took certain medications or consumed certain foods may blow higher on a breath test than they should have.

These can include:

  • Certain types of bread
  • Energy drinks
  • Kombucha or other fermented beverages
  • Mouthwash
  • Nyquil or other cough medications
  • Ripe fruit
  • Sugar-free gum

Another reason why you may blow a false positive on a breathalyzer test is ketosis. Ketosis occurs when an individual is on a low-carb diet. The breathalyzer test reads the presence of acetone as alcohol. While the test cannot make you go from 0.00 to .08, it will inflate your results and this could impact a DUI case. It could also show the presence of some alcohol on your breath when you haven’t had anything to drink.

Another reason why your breath test may have been inflated is due to the improper calibration of the breathalyzer device. Breathalyzers are a form of machinery and as such, they require routine maintenance. If the breathalyzer device is improperly calibrated, it can result in false positives even for those who have had nothing to drink.

Talk to an Orlando, FL DUI Attorney Today 

FL DUI Group represents the interests of those who have been charged with DUI in Orlando, FL. Call today to schedule a free consultation and learn more about how we can help.

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