Let’s say you were pulled over for DUI. You had had a drink or maybe two—but nowhere near enough alcohol to make you feel intoxicated.
However, the breathalyzer results show that you had a blood alcohol concentration (BAC) over the legal limit. So you are charged with Vehicle Code 23152(b) VC – driving with a BAC of 0.08% or above.
The problem here might be a medical condition like gastroesophageal reflux disease (GERD), acid reflux or a hiatal hernia. These conditions cause stomach acid to flow back into the esophagus (the “food pipe” that connects the stomach with the throat).1
If there is any alcohol in your stomach, this can create a phenomenon called “mouth alcohol.” This in turn can lead to a DUI breath test to measure a higher BAC than you actually had.
Many innocent people get arrested for DUI based on false BAC results due to GERD.
Is it possible for a DUI breath test result to be wrong?
Yes. It is entirely possible for a breathalyzer result to be wrong—especially when medical conditions like GERD/acid reflux are involved. Moreover, some medications can affect and increase blood alcohol levels.
Unlike blood tests, breath tests can only approximate the amount of alcohol in your blood. They do this more accurately if the air that is blown into a breathalyzer is “deep lung air.”2
A problem occurs when there is unabsorbed alcohol in the mouth. This “mouth alcohol” can fool a breathalyzer by combining it with the alcohol from deep lung air.3 Mouth alcohol is particularly common in GERD- or acid reflux sufferers.
Prosecutors claim that modern DUI breath testing equipment is sensitive enough to distinguish mouth alcohol from deep lung air.4 However, tests have shown that this is not always so.
How can GERD/acid reflux lead to an incorrect BAC reading?
In normal digestion, the lower esophageal sphincter (LES) opens to allow food to pass into the stomach. After eating, the LES closes to prevent stomach contents from flowing back into the esophagus.5
If the LES does not close all the way or opens too often, stomach acid and contents can flow back up into your esophagus—and even all the way to your mouth.6
If your stomach contents include alcohol, then you will end up with alcohol in your mouth—and that alcohol will show up on the results of a DUI breath test.
What is a “hiatal hernia,” and can it affect my DUI breath test?
A “hiatal hernia” is when part of your stomach pushes up through your diaphragm. It can allow food and stomach acid to pass back into your stomach—creating the same conditions as acid reflux/GERD.7
A hiatal hernia can definitely affect your DUI breathalyzer results because it, like GERD, can lead to alcohol in your stomach being pushed into your mouth. DUI breath testing equipment will then mistake that alcohol for the alcohol deep in your lungs that reflects your BAC.
How do I know if GERD or heartburn affected my breathalyzer test?
A good California defense attorney will conduct a thorough interview to see if acid reflux or heartburn might have caused a falsely high BAC reading on your breath test.
If it did, this can form the basis for a successful DUI defense based on casting doubt on your breathalyzer results.
With the help of an expert witness, your defense attorney can explain the science of DUI testing and the impact of acid reflux and heartburn to the prosecutor–and, if necessary, to the judge and jury.
The prosecutor says that GERD is not an issue. Is this true?
No.
Most mouth alcohol–including that caused by acid reflux, GERD, and heartburn–evaporates within 15 minutes. This is why Title 17 of the California Code of Regulations requires that law enforcement observe you for 15 minutes before administering a DUI breath test.8
The idea is that, by continuously observing you, the test operator can ensure that no alcohol is added to your mouth from:
- drinking alcohol,
- swishing with mouthwash, or
- vomiting or belching.
However, as Victorville DUI defense attorney Michael Scafiddi9 explains:
“Regurgitation caused by GERD, acid reflux, or heartburn is not always apparent to an onlooker. So even if the officer followed Title 17 by observing you for 15 minutes to make sure you did not burp, belch, or regurgitate, they may simply have missed the signs of regurgitation related to acid reflux.”
In other words, following Title 17 does not mean your GERD had no effect on your BAC results.
Acid reflux can trick breathalyzers into returning falsely high BACs.
Additional Reading
For more in-depth information, refer to these scholarly articles:
- Physiological Aspects of Breath-Alcohol Measurement – Alcohol, Drugs and Driving.
- The Auto-Brewery Syndrome: A Perfect Metabolic “Storm” with Clinical and Forensic Implications – Journal of Clinical Medicine.
- Alcohol and the Gastric Bypass Patient – Bariatric Times.
- Breath Alcohol Analysis in One Subject with Gastroesophageal Reflux Disease – ASTM Journal of Forensic Sciences.
- Reliability of Breath-Alcohol Analysis in Individuals with Gastroesophageal Reflux Disease– ASTM Journal of Forensic Sciences.
Legal References:
- See Mayo Clinic, GERD: Definition.
- People v. McNeal (2009), 46 Cal.4th 1183, 1191. (“When a subject blows into a breath-testing machine, the device measures the amount of alcohol vapor expelled into alveolar spaces deep in the lungs [in theory, that is–in practice GERD, acid reflux/heartburn, or a hiatal hernia can prevent this from happening].”)
- American Medical Association’s Committee on Medical Problems — Manual for Chemical Tests for Intoxication (1959). (“True reactions with alcohol in expired breath from sources other than the alveolar air (eructation, regurgitation, vomiting) [which can be caused by GERD/acid reflux] will, of course, vitiate the breath alcohol results…”)
- Jeanne Swartz, Breath Testing for Prosecutors: Targeting Hardcore Impaired Drivers, American Prosecutors Research Institute.
- Mayo Clinic, Is Acid Reflux the Same as GERD?
- WebMD, What Is Acid Reflux Disease?
- Mayo Clinic, Hiatal Hernia: Definition.
- Title 17 California Code of Regulations, Section 1219.3.
- Victorville DUI defense attorney Michael Scafiddi uses his experience as a former Ontario police officer to defend clients accused of DUI in the Inland Empire, including Hemet, Riverside, San Bernardino, and Palm Springs. He is familiar with the range of DUI defenses, including medical defenses such as GERD/acid reflux.