The Impact of GERD and Acid Reflux on California DUI Breath Tests

A DUI breath test result of 0.08 or higher does not automatically mean you were impaired. It might mean your body betrayed you. Gastroesophageal reflux disease, commonly known as GERD, and chronic acid reflux are medical conditions that can fundamentally corrupt breath test results by introducing stomach alcohol into the mouth. At Patrick Silva, Attorneys at Law, we have used this defense to dismantle breath test evidence in California DUI cases, and we know exactly how to prove that the machine was measuring the wrong thing.

How a Breath Test Is Supposed to Work

Before we can explain how GERD undermines a breath test, you need to understand what the machine is designed to measure. Evidentiary breath testing devices analyze a sample of deep lung air, also called alveolar air. This is the air from the deepest part of your lungs where gas exchange occurs between your blood and the air you breathe. Alcohol in your bloodstream diffuses into the alveolar air, and the breath test machine measures the concentration of alcohol in that air to estimate your blood alcohol concentration.

The critical assumption is that the breath sample comes exclusively from the lungs and contains only alcohol that has diffused from the bloodstream. When that assumption holds, the test has a reasonable basis for producing an accurate reading. When it does not hold, everything falls apart.

The Physiology of Acid Reflux and GERD

GERD is a chronic condition in which the lower esophageal sphincter, the muscular valve between your esophagus and stomach, fails to close properly. When this valve malfunctions, stomach contents, including partially digested food, stomach acid, and any alcohol present in the stomach, flow upward into the esophagus and can reach the mouth and throat.

Acid reflux is the broader term for this backward flow of stomach contents. GERD is diagnosed when acid reflux occurs frequently and causes symptoms or complications. Both conditions produce the same problem for breath testing: alcohol that should remain in the stomach is pushed into the oral cavity and upper airway.

Here is what happens physiologically. When you consume an alcoholic beverage, the alcohol enters your stomach and is gradually absorbed into your bloodstream through the stomach lining and small intestine. At any given time during the absorption phase, the concentration of alcohol in your stomach can be dramatically higher than the concentration in your blood. Your stomach might contain alcohol at concentrations many times greater than your actual BAC.

When GERD or acid reflux pushes that highly concentrated stomach alcohol up into your esophagus and mouth, it coats the tissues of your throat and oral cavity with alcohol vapor. If you blow into a breath test machine while this residual alcohol is present, the device captures a mixture of deep lung air and mouth alcohol. The result is a reading that is artificially and significantly inflated above your true BAC.

Why the 15-Minute Observation Period Is Not Enough

California’s Title 17 regulations require officers to continuously observe a DUI suspect for 15 minutes before administering a breath test. During this period, the suspect must not eat, drink, smoke, vomit, or regurgitate. The purpose is to ensure that no mouth alcohol is present when the test is given.

For a healthy person without GERD, 15 minutes may be sufficient for residual mouth alcohol to dissipate. But for someone with GERD, the observation period is fundamentally inadequate. GERD episodes can occur silently, without any outward signs. A micro-reflux event, in which a small amount of stomach contents rises into the esophagus, can happen without the person even realizing it, let alone the observing officer.

An officer standing across the room cannot see stomach acid creeping up your esophagus. There is no visible burp, no obvious discomfort, no sign that anything has occurred. The reflux happens internally, the alcohol vapor enters the oral cavity, and the breath test captures it. The officer checks a box on the form saying the observation period was completed, and the inflated result goes into the record as if it were gospel.

How Much Can GERD Inflate a Breath Test Result?

The degree of inflation depends on several factors, including how recently you consumed alcohol, the severity of your reflux condition, and the timing of the reflux event relative to the breath test. However, research has shown that mouth alcohol contamination can produce readings that are substantially higher than the person’s actual BAC.

Consider this scenario: your true BAC is 0.05, which is under the legal limit. You have mild GERD that causes occasional silent reflux episodes. Shortly before the breath test, a small amount of stomach contents, including alcohol at a high concentration, refluxes into your esophagus. When you blow into the machine, the device picks up both the alveolar air (reflecting your true 0.05 BAC) and the residual stomach alcohol in your mouth. The result could register at 0.09, 0.10, or even higher, pushing you well above the legal limit based on an artifact of your medical condition rather than actual impairment.

This is not a theoretical problem. It happens regularly, and it results in wrongful DUI charges against people who were legally sober.

Proving GERD as a Defense in Your DUI Case

Using GERD or acid reflux as a defense requires more than simply telling the court you have heartburn. We build these defenses methodically:

Medical records and diagnosis. We obtain your medical history showing a documented diagnosis of GERD or chronic acid reflux. Records from your gastroenterologist, primary care physician, or other treating providers establish that you have a condition capable of producing the mouth alcohol contamination we are alleging.

Prescription and medication records. Many GERD patients take proton pump inhibitors (PPIs) such as omeprazole or H2 blockers like famotidine. Your medication history corroborates the diagnosis and demonstrates the ongoing nature of the condition.

Testimony from medical professionals. We work with physicians and forensic toxicologists who can explain to a judge or jury exactly how GERD causes mouth alcohol contamination and why the breath test result in your case is unreliable. This testimony connects the medical science to the specific facts of your case.

Challenging the observation period. We scrutinize the officer’s observation period documentation. Was the officer truly watching you continuously for 15 minutes? Were they filling out paperwork, talking on the radio, or looking away? Even a brief lapse in observation, combined with a GERD diagnosis, can be enough to cast serious doubt on the breath test result.

Breath test patterns. If two breath samples were taken and the results differ by more than 0.02, this inconsistency may suggest the presence of mouth alcohol. We analyze the specific readings and the time between samples to support our argument.

Other Medical Conditions That Cause Similar Problems

GERD is the most common medical condition affecting breath tests, but it is not the only one. Several other conditions can produce similar mouth alcohol contamination:

Hiatal hernia. A hiatal hernia occurs when part of the stomach pushes through the diaphragm into the chest cavity. This structural abnormality makes reflux episodes more frequent and more severe.

Esophageal conditions. Strictures, motility disorders, and other esophageal conditions can trap alcohol in the esophagus and allow it to vaporize during a breath test.

Diabetes and ketoacidosis. Diabetic ketoacidosis produces acetone in the breath, which some breath testing devices may misidentify as ethanol. While newer machines are designed to distinguish between the two, the risk of a false reading still exists.

Dental work and oral conditions. Dentures, bridges, and gum disease can trap alcohol in the mouth, creating pockets of residual alcohol that persist beyond the observation period.

If you have any of these conditions, the reliability of your breath test result is questionable, and we will investigate it thoroughly.

Why Prosecutors Hate This Defense

Prosecutors hate the GERD defense because it attacks the foundation of their case. The breath test number is typically the strongest piece of evidence they have. When we demonstrate that the number cannot be trusted, the prosecution’s case weakens dramatically.

They will try to counter by arguing that the observation period was properly conducted, that the machine functioned correctly, and that your medical condition is irrelevant. We respond with science, medical evidence, and the hard reality that breath testing machines cannot distinguish between alcohol from your lungs and alcohol from your stomach. That is a mechanical limitation of the technology, and no amount of prosecutorial argument can change it.

Patrick Silva, Attorneys at Law Will Expose the Flaw in Your Breath Test

A breath test number is not a conviction. It is a data point, and data points can be wrong. If you have GERD, acid reflux, or any condition that affects your digestive system, the breath test used against you may be measuring something entirely different from your actual blood alcohol level. At Patrick Silva, Attorneys at Law, we have the education, the scientific understanding, and the courtroom experience to prove it. Our DUI defense results across San Bernardino County and our reputation online reflect the level of preparation we bring to every case.

Stop assuming the machine was right. Call us at 909-500-4819 and let us examine what really happened.