What Can Cause a False Positive on a Breathalyzer Test?

A DUI conviction can have severe penalties. You could lose your freedom and carry a criminal record for the rest of your life. A DUI case could affect your employment, either getting you fired or ending your hope of getting hired by certain companies. A DUI charge could even interfere with child custody disputes.

Sadly, all this could occur after a false positive reading on a breath test. In other words, the evidence prosecutors use against you could include faulty breath test results. Understanding how these false positive readings occur can help you defend against them. Contact the Dayton DUI & OVI lawyers at Gounaris Abboud to discuss your DUI arrest and how we defend you against faulty breathalyzer tests.

What Is a False Positive Breathalyzer Test?

All measuring devices have inherent inaccuracies. Breathalyzer devices are no different. However, no one serves jail time if your bathroom scale is off by 1%. However, a 1% error in a breath test can result in a wrongful conviction.

To convict someone of OVI, a breath test must detect 0.08 grams of alcohol per 210 liters of breath. For context, 210 liters is about 55.5 gallons, and 0.08 grams is roughly the weight of two to four grains of rice. Even non-engineers can appreciate that any number of factors could affect the accuracy of this measurement.

What Foods Can Make You Fail Breathalyzer Tests?

Breathalyzer equipment contains potassium dichromate, which reacts with ethyl alcohol to generate an electric current. The device indirectly measures alcohol by measuring the current.

Fermentation produces alcohol in beer, wine, and spirits. However, yeasts and bacteria in your digestive tract can react with sugars, starches, and proteins to produce alcohol vapor, triggering a false positive breath test. Foods and drinks that can cause false positive breath tests include:

• Bread
• Kombucha and other fermented sodas and teas
• Hot sauce
• Vanilla extract
• Natural energy drinks like yerba mate

People on high protein, low carb diets are also susceptible to faulty breathalyzer readings.

What Medications Can Affect a Breathalyzer Test?

If you have certain medical conditions, your medication can affect breathalyzer tests. In particular, some medications use alcohol as a solvent or carrier. Other medications get metabolized into alcohol after consumption.

Alcohols refer to a chemical family, only one of which is consumed as liquor. These alcohols can react with potassium dichromate to produce an incorrect reading that suggests you were drinking alcohol, even when you did not. Examples of these medications include:

• Cough and cold medication
• Alcohol-based mouth sore and toothache remedies
• Asthma inhalers
• Sleeping medication
• Vitamins
• Protein bars and supplements

Unfortunately, medications rarely warn of this side effect.

What Environmental Factors Can Impact Positive DUI Test Results?

What besides alcohol can set off a breathalyzer? Fumes from some products can generate false positives on a DUI breathalyzer test. The sensors can detect residue on your lips, skin, or clothing, generating a false positive result.

Thus, a positive result does not mean your blood alcohol concentration is above the legal limit. Instead, it simply means the test detected the chemicals you touched or inhaled. Some chemical products that can cause a false reading include:

• Paints
• Alcohol-based cleaners
• Adhesives
• Solvents

These products can also cause dizziness and disorientation when you inhale the fumes. As a result, law enforcement officers may incorrectly believe your abilities are impaired by alcohol.

What Other Common Items Can Cause False Positives in a Breathalyzer Test

What can affect a breathalyzer test besides food and medication? A false positive reading can result from less obvious sources. These causes of false high BAC can either introduce alcohol into the testing device or produce conditions in which the test device mistakenly reports blood alcohol content above the legal limit. Some additional factors to consider include the following:

Health Factors That Trigger a False Positive on a Breathalyzer

Acid reflux disease can cause you to burp gas that contains digestion byproducts, such as fermented food that contains trace amounts of alcohol. Rather than detecting alcohol from your lungs, the device would detect alcohol in your stomach. More importantly, it would not necessarily detect ethanol but rather natural fermentation byproducts.

A diabetic can suffer ketoacidosis when their body cannot use blood sugar and burns fat instead. The ketones on their breath can cause a false positive result for alcohol. Worse yet, another symptom of ketoacidosis is confusion, leading officers to believe the driver is impaired by alcohol.

Drivers who wear dentures or have bad oral hygiene might receive false positive results when food trapped in their teeth ferments and produces minuscule amounts of alcohol. Since the breathalyzer devices must detect tiny amounts in the breath, this source of alcohol can skew the results.

Hygiene Products Which Lead to a False Positive on a Breathalyzer

Hygiene products that contain alcohol, such as mouthwash, aftershave, and hand sanitizer, can corrupt breathalyzer test results. Aerosols might use rubbing alcohol as a carrier. Products like spray deodorant, hairspray, and insect repellant can produce a fine alcohol mist during and after application. The testing device can mistake the fumes from these products for alcohol vapor in your breath.

The device can even detect alcohol from the officer conducting the test. If the officer uses hand sanitizer before touching the mouthpiece, the breathalyzer might tell you the alcohol content of the officer’s hands rather than the driver’s breath.

Mouth Alcohol That Causes a False Positive Breathalyzer Reading

The scientific principle behind breathalyzer tests is that the alcohol on your breath correlates to the alcohol in your blood because your heart circulates blood to your lungs. However, there is no way to determine whether the alcohol that reaches the testing device came from your lungs or mouth.

Specifically, alcohol in your mouth that never reaches your stomach will not intoxicate you because it never reaches the brain. However, it can trigger a false positive breathalyzer result as you breathe alcohol vapor out of your mouth and into the device. This mouth alcohol effect can happen when you eat foods cooked in alcohol. It can also result from wine tasting, where you spit the sample out.

Poor Equipment Calibration Leading to a False Positive BAC Test

What can make you fail a breathalyzer besides alcohol? Law enforcement officials can introduce testing errors when they use uncalibrated or contaminated testing equipment. Specifically, police officers must periodically clean and calibrate their breath test devices. Alternatively, the manufacturer will service and maintain these devices if police departments remember to send them in.

Cleaning is essential since prior tests can leave alcohol residue inside the reaction chamber. As a result, the device will contain alcohol that was not captured from the driver’s breath. Instead, it will contain alcohol from several drivers, leading to breathalyzer results that are incorrectly high.

Similarly, these devices must be calibrated periodically to make sure they are accurately detecting alcohol. If the reagent in the device has become adulterated or the ammeter incorrectly measures the current resulting from the reaction, the device will provide unreliable results.

Operational and Human Error Issues Inducing a Wrong Breathalyzer Test

What can cause a false breathalyzer reading other than you? Police departments must train their officers in the proper testing protocols for producing accurate BAC readings. If the department does not conduct training or the officers do not follow the procedures, they can introduce measurement errors that produce inaccurate readings.

Some operational errors that police officers or lab technicians might commit include the following:

• Failing to conduct the test as instructed by the manufacturer.
• Failing to run diagnostics to detect malfunctions.
• Neglecting to send devices for repair when they break or produce error codes.
• Incorrectly interpreting or recording test results.

Law enforcement agencies can also introduce errors. For example, they might buy the least expensive devices rather than the most accurate ones. As a result, all of their BAC tests might be questionable.

To challenge tests, your lawyer will examine the practices of the police department and its officers to identify any possible sources of error. Prosecutors bear the burden of proof in an OVI prosecution. Thus, your lawyer will look for any false positives on breathalyzer for alcohol testing introduced by the officers. This evidence will undermine the government’s evidence against you.

What Happens If You Fail a Breathalyzer Test?

Ohio’s OVI statute includes two violations. First, you violate the law by driving while impaired by drugs or alcohol. A conviction for this violation does not require a failed test.
Second, you commit a per se violation when you drive with a blood alcohol content (BAC) over the legal limit. This violation happens when you fail an alcohol test.

The severity of your punishment depends on your BAC level and whether you are a repeat offender.

What to Do If You Think Your Breathalyzer Was a False Positive

If you believe your breath sample was incorrectly measured, contact a lawyer familiar with the causes of false positive blood alcohol test results. Also, gather the evidence they need to disprove the test. Can you fail a breathalyzer without drinking? Yes. You should document the food, medication, and hygiene products you came into contact with before your test.

Depending on the source of error, your lawyer may need to hire an expert witness. This scientist or engineer will explain to the jury what happened to your test.