Can My Medical Condition Cause False Results on My Nevada DUI Breath Test?

breathalyzer showing .13 BAC

How GERD, diabetes, diet and other medical conditions can “fool” Nevada DUI breath tests

You had your last drink hours ago, but suddenly you feel drunk for no apparent reason. Or maybe you don't feel drunk at all.

Yet when you get pulled over for a traffic violation, the officer suspects you of drunk driving and a Nevada DUI breath test confirms you are over the legal limit.

What's going on?

If you suffer from certain medical conditions, your physical symptoms could be “tricking” a Breathalyzer into thinking you are drunk. Medical conditions that can cause false “positives” on DUI breath tests include:

An experienced Nevada DUI lawyer who is not afraid of the science can often – with the help of expert testimony – show the prosecutor and/or jury how your medical condition produced a falsely high BAC reading. And when this happens, the result is often that your DUI charges get reduced or even dismissed.

To help you understand how a medical condition might lead to an erroneous DUI breath test result, our Reno and Las Vegas DUI defense lawyers discuss the following below:

teenage driver with multi-colored hair in driver's seat holding her hand to her face

1. How Nevada DUI breath tests work

Under Nevada DUI law you drive under the influence when:

Unlike a Nevada DUI blood test, a DUI breath test cannot directly measure the percentage of alcohol in your blood.

Instead, DUI breath testing devices measure the amount of alcohol in your breath and mathematically convert it to a roughly equivalent BAC.

In Nevada, the evidentiary breath testing device currently in use is the Intoxilyzer 8000. The Intoxilyzer 8000 uses Infrared Spectroscopy to analyze the amount of alcohol in a person's breath.

1.1. The science of DUI breath testing

To get an accurate reading, the Intoxilyzer 8000 and other “Breathalyzers” must measure the alcohol present in your “deep lung” air. This is the air that is closest to your blood supply.

To understand why, consider that when we exhale, air emerges in the following "reverse" order:

  1. From the mouth/nasal area, then
  2. From the throat and upper airway, and finally
  3. From the alveoli, located deep within the lungs.

The alveoli are balloon-like sacs which inflate when we inhale and deflate when we exhale. The alveoli sit just above the capillaries, slender blood vessels no more than 1/1000 of a millimeter thick.

chart showing how alcohol moves from capillaries into lungs

When we breathe, oxygen passes from the lungs into the capillaries. The capillaries, in turn, pass carbon dioxide and other wastes from the blood into the alveoli. These wastes are then gotten rid of when we exhale.

Because the capillaries are thin enough to allow the passage of oxygen and wastes, however, they can also pass a fraction of any alcohol present in the blood into the alveoli. This is why you are asked to blow hard when you take a breath test.

Not everyone is capable of blowing hard enough for a reliable breath test reading. Older people -- and those with conditions, such as asthma, that make it difficult to take a deep breath -- may have trouble generating the volume of air required. Breath testing devices are calibrated to return an error message if enough air is not generated. If you are unable to blow hard enough, you will usually be required to take a Nevada DUI blood test instead.

2. How medical conditions can cause unreliable Nevada DUI breath testing results

In order to collect deep lung air, Nevada evidentiary DUI breath testing devices of necessity also collect air from your throat and mouth. This is because deep lung air must pass through your throat and your mouth in order for the device to capture it.

After ingesting alcohol, however, some of the alcohol remains in the mucosal linings of your mouth for a short period of time. This is known as “residual mouth alcohol.”

Imagine, for instance, that you swish wine around in your mouth at a wine tasting and then spit it out. A DUI breath test reading done immediately after would likely put you over the legal limit, even though you didn't swallow and couldn't, therefore, be drunk.

man sniffing a glass of red wine

Mouth alcohol usually dissipates in 15-20 minutes or less. This is why Nevada law requires that you be observed for a 15-minute period before you are given an evidentiary breath test after a Nevada DUI arrest. It is to ensure that any residual mouth alcohol is completely gone at the time of your DUI breath test.

2.1. Digestive disorders

Mouth alcohol can also result from certain digestive disorders. In particular, conditions such as gastroesophageal reflux disease (GERD) and acid reflux -- in which acid or alcohol from the stomach flows back into the esophagus – can trick a breathalyzer into thinking you are drunk.

Prosecutors claim that modern DUI breath testing equipment is sensitive enough to distinguish mouth alcohol from deep lung air. However, tests have shown that this isn't always so.

To learn more about digestive disorders and DUI, please see our article: How GERD, reflux, heartburn and hiatal hernia can “trick” Nevada DUI breath testing devices.

2.2. Diets, diabetes, hypoglycemia and other conditions affecting blood sugar

Mouth alcohol also occurs in people who suffer from diabetes or hypoglycemia, or are fasting or on severe high-protein, low carbohydrate diets.

Healthy bodies normally get energy from carbohydrates in the diet. When we eat carbohydrates, our digestive systems break them down into sugars. One of these sugars is glucose, our bodies' main energy source.

Glucose passes from the digestive tract into the bloodstream (which is why it's often referred to as “blood sugar”). If we don't eat enough carbohydrates to produce the blood sugar we need – because of dieting or starvation – our body must turn to our fat stores.

Fat is broken down in the liver and is turned in various chemical substances, including those known as "ketone bodies" or "ketones," and isopropyl alcohol. In the absence of glucose, our bodies can burn ketone bodies for fuel. In the process of turning fats into ketones, however, the liver also produces a form of isopropyl alcohol (acetone).

Excess ketones (and isopropyl alcohol) is excreted in the urine and the urine and breath. Breath testing device manufacturers claim that their equipment can tell the difference between ethyl alcohol (the kind found in alcoholic beverages) and isopropyl alcohol. However, this isn't always the case.

Thus people on high-protein or crash diets -- or those who suffer from diabetes or hypoglycemia -- are susceptible to false "positives" on Nevada DUI breath tests.

To learn more about how your diet and medical conditions involving blood sugar can affect DUI test results, please see our articles: DUI and high-protein diets, Diabetes as a DUI Defense in Nevada, and How Hypoglycemia Can "Trick" a Nevada DUI breath test.


Arrested for DUI based on a medical condition? Call us for help…

Hundreds of people who suffer from medical conditions are arrested for DUI each year, simply because a breath test produced a falsely high reading.

Our caring Las Vegas and Reno DUI defense attorneys understand the science behind DUI breath testing. We know that it is entirely possible for a Nevada DUI breath test result to be wrong.

If you have been charged with DUI and think a medical condition or your diet may be to blame, we invite you to contact us for a free consultation. One of our knowledgeable DUI defense lawyers will go over your case to help you determine the best defense to your Nevada DUI charges.

To schedule your free consultation call us at 702-DEFENSE (702-333-3673) or fill out the form on this page.

To learn how to fight a DUI in California, please see our article: 20 Ways to Beat a California DUI.


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