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How Common Is a False Breathalyzer Reading?

A Breathalyzer device is a machine or device commonly used by law enforcement officials to measure the blood alcohol content (BAC) of an individual, such as a driver during a traffic stop who is suspected of DUI. Some devices are portable so they can be easily transported by law enforcement officers. Other models are designed to be stationary and placed in police stations. These devices are marketed and sold under various brand names, including Alcosensor, Intoxilyzer, BAC Datamaster, and Alcoscan.

Although many Breathalyzer devices are on the market, they all work in basically the same manner. Breathalyzers measure the alcohol content in a person’s breath, as opposed to alcohol blood tests, which directly measures BAC. Through an alcohol content measurement, the Breathalyzer device estimates the person’s BAC. It is well-established that alcohol blood tests are the most accurate way to determine a person’s BAC. However, due to their expense and inherently intrusive nature, i.e. drawing blood from a person’s body, Breathalyzer machines are the most common tool used by law enforcement to evaluate an individual’s BAC. Law enforcement agencies in all states rely heavily on Breathalyzer tests to charge individuals with DUI. Likewise, prosecutors often use Breathalyzer results as the basis for DUI convictions. Nonetheless, a variety of outside factors can directly affect the accuracy of breath test results, as can errors in the administration of Breathalyzer devices. As a result, some studies estimate that about 23% of individuals tested using this method will have an actual BAC that is significantly lower than the BAC reading, sometimes by up to 15%. Since BAC levels can govern whether a person is convicted of DUI, and in some states, the degree of the crime charged, having potentially false or misleading BAC results is extremely problematic. Let’s take a closer look at some of the outside factors and errors in administration that may affect the outcome of a Breathalyzer test.

Gastroesphageal Reflux Disease (GERD) and Breathalyzer Results

There are some medical conditions that directly impact an individual’s BAC reading. For instance, gastroesphageal reflux disease (GERD) is one medical condition that can directly affect the results of your Breathalyzer test. In fact, it can create a false positive reading or a test reading error. Most Breathalyzer machines are designed to measure alcohol content in the lining of your lungs. However, medical experts advise that it is the air deepest in an individual’s lungs that provide the most accurate measure of blood alcohol content. In an individual who suffers from GERD, alcohol actually can move from the stomach to the back of the throat. Therefore, an individual with GERD may register a much higher and wholly inaccurate BAC reading when taking a Breathalyzer test.

Likewise, even individuals without GERD may register incorrect BAC readings from a Breathalyzer if they have recently eaten a meal that produces a great deal of acid reflux, such as meals that are extremely greasy or spicy. The presence of acid in one’s breath or mouth can skew the BAC results to produce a false outcome. As a result, the presence of GERD in an individual may serve as a defense to DUI charges based on Breathalyzer test results.

Breathalyzer Results and Other Chemical Compounds

A Breathalyzer machine does not really measure alcohol, per se. Rather, it typically measures the level of the methyl group of chemical compounds, which the device assumes is ethyl alcohol. This is particularly the case with infrared breath testers. There are 70 – 80 different types within the methyl group structure. The problem with this fact about Breathalyzers is that other chemical compounds may be present in an individual’s breath that can cause false positive Breathalyzer test results. Some of these chemical compounds may exist in a person’s breath from the following activities:

  • Breathing in gasoline, oil-based paint, propane, or varnish fumes
  • Acetone production, commonly found in the breath of diabetics, as well as individuals who have gone on the Atkins diet or other types of low-carb diets involving fasting.
  • Production of so-called “mouth alcohol” from the following:
    • Burping and belching
    • Denture
    • Periodental disease
    • Vomiting
  • Consumption of Listerine, other types of mouthwash, breath strips, and breath spray
  • Usage of some medications, including:
    • Nyquil
    • Albuterol
    • Cough syrup
    • Cold medicine
    • Toothache medicine
  • Consumption of certain bread products
  • Consumption of foods containing liqueurs
  • Usage of lip balm
  • Usage of smokeless menthol tobacco
  • Prescribed use of inhalants, such as salbutamol, salmeterol, and budesonide, which are commonly used to treat asthma

One study estimates that the presence of acetone, for instance, can add a 0.06% BAC reading to any existing alcohol content, or even create a 0.06% BAC reading in someone who has drank no alcohol at all. On the other hand, it is a myth that substances that mask the odor of alcohol affect Breathalyzer results. Eating mints, onions, and garlic may cover up alcohol odors, but will not affect a Breathalyzer reading one way or another. Therefore, while the substances listed above can impact a Breathalyzer test result, substances that merely alter the odor of alcohol will not impact it.

Air and Body Temperatures and Breathalyzer Results

Another outside factor that can significantly alter Breathalyzer test results is temperature, include body temperature and air temperature. Having a fever at the time you undergo a Breathalyzer test can result in inaccurate results, as well. On average, for every 1 degree that your body temperature is above normal, your BAC reading will increase by 8%.

Likewise, an individual’s breathing rate also can have a direct impact on his or her BAC reading, as measured by a Breathalyzer. Vigorous exercise, hyperventilation, or holding one’s breath for only 30 seconds can substantially affect a BAC rate, by as much as 10%.

Finally, weather temperature can affect BAC readings, as well. If the Breathalyzer device is not calibrated or adjusted in order to account for the outdoor temperature, a Breathalyzer test that is administered outdoors may display an incorrect reading.

Radio Frequency Interference (RFI) and Breathalyzer Readings

With any instrument that contains electronic circuitry, including Breathalyzer devices, there is the chance that electromagnetic interference (EMI) from other devices can interfere with the instrument’s readings or results. This phenomenon is perhaps best illustrated by the effect that a microwave can have on a person’s pacemaker.

Other instruments, however, including many instruments commonly found at police stations, such as dispatch radio transmitters, walkie-talkies, cell phones, computers, and even fluorescent lighting can create such interference. As a result, the presence of these instruments can skew Breathalyzer result readings. Again, this type of interference can be the basis for challenging the accuracy of Breathalyzer test results in DUI cases.

Lack of Proper Maintenance and Testing

Another potential flaw in Breathalyzer devices is a lack of routine maintenance and appropriate testing. As highlighted by a recent Oklahoma Supreme Court case, Breathalyzer results may be insufficient to establish DUI where the results may be flawed due to a lack of maintenance or testing standards for the Breathalyzer used in the case. More specifically, the police department involved in the case had no written standards or procedures governing the testing or maintenance of these devices; as a result, the machines were used for about five years without any testing to determine that their readings were still accurate.

Another issue related to the maintenance of Breathalyzer machines is the need to calibrate the devices on a regular basis. If these devices are not regularly maintained and calibrated as needed, the results of an individual’s Breathalyzer test can be inaccurate. Law enforcement officials must maintain accurate records of calibration and maintenance of every Breathalyzer device used. If they fail to do so, then these elements are easily challenged in many DUI cases.

Lack of Training and Officer Inexperience

Police officers should be properly trained in the use of Breathalyzer devices in order to ensure that they are appropriately administered. For example, these devices often need to be calibrated prior to use. An inexperienced officer may fail to properly calibrate or otherwise ready the device before administering a Breathalyzer test during a traffic stop. This improper administration of the test may render results that are simply incorrect.

Be Cautious in Evaluating Breathalyzer Test Results

As these many examples illustrate, Breathalyzer test results can be affected by a wide variety of factors, ranging from environmental factors to medications, from consumption of certain products to operator error. The documented lack of accuracy in Breathalyzer test results can be an integral part of a strong defense to DUI charges. Given the many different circumstances that can affect a BAC reading taken from a Breathalyzer test, there are many alternatives available for challenging the test results. These challenges can lead to grounds to negotiate a lesser charge or penalty, or even to the dismissal of charges in some cases.

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