Medical Conditions That Falsely Raise a Breath Test

Can a medical condition cause a false DUI breath reading?

The Machine Assumes You Are Average

Breath testing is built on assumptions about a normal, healthy body. Many people are not that.

The Intoxilyzer converts a breath sample into a blood-alcohol estimate using fixed assumptions, a standard partition ratio, a normal digestive system, no interfering compounds. When your physiology breaks those assumptions, the number breaks with it, and the machine has no way to know.

Acid Reflux & GERD (Mouth Alcohol)

Reflux brings stomach contents, and alcohol, back into your mouth, defeating the test.

If you have GERD, acid reflux, or a hiatal hernia, stomach contents can travel back up during the test, depositing mouth alcohol that the machine reads as a high blood level. This is exactly the error the 15-minute observation is meant to catch, and reflux can occur silently, without an obvious burp.

A documented reflux condition, paired with a flawed observation period (see our breath-test guide), is a powerful challenge to a breath result.

Diabetes, Ketosis & Low-Carb Diets

Your metabolism can create compounds the machine mistakes for alcohol.

Two common situations inflate breath readings without drinking:

• Diabetes / hypoglycemia, uncontrolled blood sugar produces ketones and acetone that some breath machines read as alcohol, and the symptoms (confusion, slurred speech, poor balance) can also be mistaken for impairment.
• Low-carb / keto diets & fasting, ketosis produces acetone on the breath, which can register as alcohol.
• Auto-brewery syndrome, a rare gut condition that ferments carbohydrates into alcohol internally.

These are not excuses, they are documented physiological facts a medical expert can tie directly to your reading, and to why field sobriety “clues” may have nothing to do with alcohol (see field sobriety defense).

Conditions & Situations That Can Inflate a Breath Test

A breath machine cannot tell body-produced compounds from drinking. These are the common culprits.

Physiological Causes of a False High Reading

• GERD, acid reflux, or a hiatal hernia, mouth alcohol from stomach contents.
• Diabetes / diabetic ketoacidosis, ketones and acetone read as alcohol.
• Keto, low-carb, or fasting, ketosis produces acetone on the breath.
• Auto-brewery syndrome, gut fermentation produces alcohol internally.
• Recent vomiting or burping, fresh mouth alcohol.
• Dental work, dentures, or braces that trap alcohol.

Symptoms Wrongly Read as “Impairment”

• Diabetic episodes, confusion, slurred speech, poor balance, sweating.
• Fatigue and anxiety, shaky performance on roadside tests.
• Medications and medical nystagmus, eye movement mistaken for the HGN test.
• Injuries or inner-ear issues, balance problems unrelated to alcohol.

Explaining the Number to a Jury

A credible medical explanation turns a damning number into reasonable doubt.

When a physician or toxicologist explains that your condition can produce the exact reading the State relies on, the number loses its power. That regularly leads to reduced charges, dismissals, and acquittals, especially when combined with breath-machine and observation defects.

Part of a full defense, see the Top 10 DUI defenses and Phoenix DUI defense. Call 623-321-4699, 24/7.