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False Breathalyzer Readings: What You Should Know


DUIs are treated seriously throughout the country, given that drinking and driving is a major leading cause of fatal car accidents. Law enforcement officers often pull over drivers who swerve, drive erratically, or show other telling signs of intoxication they are trained to look out for. If you are pulled over for a suspected DUI, you will be asked to submit to a breathalyzer test. While many of us accept that these tests are generally infallible, the truth is that they are far from perfect and false readings are not as uncommon as you might think.

Freshening Your Breath

Even if you have never been pulled over by a law enforcement officer who suspected you were driving while under the influence of alcohol, chances are you have seen the portable breathalyzer tests they carry and use during traffic stops. Have you ever wondered how they work? A breathalyzer test essentially detects the presence of alcohol in your breath. However, there are other things beside your favorite cocktail that contain alcohol and any number of them could potentially lead to a false positive result.

For example, if you rinse your mouth with mouthwash prior to heading out, this could set you up for a false positive. Mouthwash has an incredibly high alcohol content and, though some manufacturers are now creating concoctions that only contain fluoride, you can never be too careful. Additionally, mints, gum, cough drops, and even tobacco can potentially cause you to blow a false positive during a breathalyzer test.


Other culprits beside breath fresheners can cause a breathalyzer to provide a false positive result. Police officers are not perfect and, while calibrating the breathalyzer, he or she might set it incorrectly. Unfortunately, these mistakes cost others and a simple error in calibration can lead to multiple arrests based on inaccurate information. A breathalyzer test is a machine and, like all machines, it needs to be regularly maintained to ensure the information it is providing is as precise as possible. Without proper calibration or upkeep, officers will undoubtedly make arrests that cannot be supported in court, creating serious hardships for innocent citizens.


A fair amount of medications can also potentially interfere with the results of a portable breathalyzer test. Generally, any medication that is applied inside the mouth likely contains alcohol and could affect the accuracy of this test. For example, if you use Anbesol to relieve canker sore pain or a toothache, you risk blowing a false positive since it will detect the medication rather than your blood alcohol level.

Remember to exercise particular caution during the winter since many treatments for cold and flu symptoms contain alcohol and could show up on your results for a portable breathalyzer test. You should also generally be careful while operating a motor vehicle when you have a cold and are self-medicating since you might appear impaired to an officer, bolstering suspicions even further.

If you are a diabetic, you can blow a false positive depending on your blood sugar level. It is not uncommon for diabetics to have acetone levels that are significantly higher than the average non-diabetic. If the portable breathalyzer is older, it might not be able to differentiate between alcohol consumed and ethyl alcohol. Of course, every situation is different, which is why it is critical to hire a skilled criminal defense attorney who is experienced in handling DUI cases.

Other Factors

There are a variety of other factors that, though they are less common, can still be responsible for a false positive result on a breathalyzer test, which include:

  • Software - Some breathalyzers run on special software and, just like any other form of technology, there is always the occasional bug and glitch that could lead to a false positive result for an unsuspecting innocent person.
  • Human error - Even if the breathalyzer is correctly calibrated it still needs to be used properly. If the officer administering the test is inexperienced or simply does not know how to use the breathalyzer appropriately, there is no telling what could happen with the results.
  • Consistency - Breathalyzer tests should always be performed more than once to ensure accuracy. If the machine keeps producing inconsistent results, something might be wrong with the machine itself, but the officer will be unaware of this if he or she only performs it once.
  • Environmental factors - A false positive result could also be triggered by outside elements, such as paint fumes, varnish, and other chemicals.

DUI Defense Attorney in Quincy

If you are currently facing DUI charges, it is critical that you seek skilled legal representation as soon as possible to protect your rights and future. At Flanagan & Associates, our Quincy criminal defense attorney is dedicated to providing fierce legal advocacy to help ensure the best possible outcome for your case. Let us fight on your behalf for your freedom and interests.

Contact our office today at (781) 332-4344 to schedule a free case evaluation with a knowledgeable member of our team.

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