In DUI cases, breathalyzer test results are often treated as solid evidence of intoxication; however, these devices are far from foolproof. While they measure alcohol on your breath to estimate your blood alcohol concentration (BAC), numerous substances and situations can throw off their accuracy.
If you’re facing a DUI charge in South Carolina, knowing what can interfere with a breath test may be critical to your defense.
Prescription Inhalers and Asthma Medications
Medications used to treat asthma, such as bronchodilators and steroid-based inhalers, can contain alcohol-like compounds. When used shortly before a test, these substances may linger in your mouth and cause the breathalyzer to produce a falsely elevated reading, even if you haven’t consumed any alcohol.
Cold and Flu Products
Over-the-counter medications like cough syrups, nighttime flu relief liquids, and certain decongestants often contain small amounts of alcohol. Even medicated cough drops or sprays with alcohol-based carriers can temporarily affect breathalyzer readings if taken near the time of the stop.
Oral Pain Relievers
Topical products used for dental discomfort, such as gels or numbing agents, can contain ingredients that mimic alcohol compounds. When left on the gums or tongue, they can be misread by the breathalyzer sensor, creating results that don’t reflect true intoxication.
Mouthwash and Breath Fresheners
Many commercial mouthwashes, sprays, and mints contain high concentrations of alcohol (sometimes up to 30%). While these products don’t cause impairment, they can inflate breathalyzer results if used within minutes of testing. In these cases, the alcohol measured is residual—not from your bloodstream.
Environmental Contaminants
Working around certain chemicals, like solvents, paints, cleaning products, or gasoline, can create residual vapors in your lungs or clothing. Some breathalyzer models are sensitive enough to detect these fumes and confuse them with ethanol, the type of alcohol the device is designed to measure.
Fermented Foods and Baked Goods
Believe it or not, consuming items like sauerkraut, soy sauce, ripe bananas, or bread made with yeast can produce trace amounts of ethanol in your mouth. While this won’t impair you, the fermentation process can produce alcohol byproducts that skew the breathalyzer’s reading if tested shortly afterward.
Certain Medical Conditions
Your health can play a major role in BAC readings:
- Acid reflux (GERD): Can push alcohol from the stomach into the throat or mouth, leaving residual alcohol that falsely elevates the result.
- Diabetes: High levels of ketones, a compound diabetics produce during blood sugar imbalances, can be mistaken by some devices for alcohol due to their chemical similarity.
- Diet-induced ketosis: Low-carb or high-fat diets can also elevate ketone levels, leading to potential misreadings.
Testing Errors and Device Issues
Even if none of the above applies, the breathalyzer itself could be the problem. These machines require regular calibration and must be used according to strict procedures. If the test was administered improperly or the device hadn’t been maintained, the result may not be reliable.
The Bigger Picture: Your Breath Test Result Isn’t the Final Word
Too often, breathalyzer results are treated as absolute proof of impairment. But in reality, they’re just one piece of evidence, and not always a reliable one. As your defense attorney, I’ll evaluate every factor that could have affected your test: your medications, diet, environment, medical history, and whether the device was used correctly.
Thinking About Refusing a Breathalyzer? Know the Risks and Rights
In South Carolina, refusing a breath test has immediate consequences, including license suspension. But in some cases, refusal may prevent unreliable or inflated results from being used against you. To better understand the implications of refusing to “blow” during a DUI stop, visit our companion guide: When You Choose to Refuse
Charged with DUI in Anderson, Greenwood, or elsewhere in the Upstate?
Don’t let a faulty test determine your future. Contact Austin McDaniel today for a FREE confidential case review, and take the first step toward defending your rights and your record.