If you are diabetic and you were arrested for DUI, your own body may have helped build the case against you. Diabetes can both fool a breath machine into reading high and produce symptoms that look exactly like intoxication. I am Joel Brand, and this is one of the most compelling medical defenses there is.
How diabetes fools the breath machine
When a diabetic's blood sugar runs high or low, the body produces ketones, including acetone. Acetone is a chemical cousin of isopropyl alcohol, and many breath-testing devices cannot reliably tell it apart from the ethanol they are supposed to measure. The result can be a reading well above your true blood alcohol level, or a reading where there should be almost none. The machine reports a single number as if it were certain, but that number can reflect the chemistry of an uncontrolled diabetic body rather than anything you drank.
The science of ketoacidosis
When the body cannot use glucose for fuel, it burns fat instead, and that process generates ketones in a state called ketoacidosis. Diabetic ketoacidosis is a recognized medical condition, and one of its byproducts is acetone on the breath. Infrared breath machines measure alcohol by detecting molecules with a particular chemical structure, and acetone shares enough of that structure to be misread as ethanol on many devices. A person in or near ketoacidosis can therefore blow a falsely elevated result while having consumed little or no alcohol, which is exactly the scenario the prosecution does not want explained to a jury.
How it mimics impairment
Hypoglycemia, or low blood sugar, produces confusion, slurred speech, unsteadiness, drowsiness, sweating, and poor coordination. To an officer running field sobriety tests on the roadside, that looks like a drunk driver. It is actually a medical emergency that has nothing to do with alcohol. The cruel irony is that a diabetic experiencing a genuine medical crisis can be arrested, booked, and charged precisely because the symptoms of that crisis are mistaken for intoxication, when what the person actually needs is sugar or medical attention.
Why officers miss it
Officers are trained to spot impairment, not to diagnose medical conditions, and a diabetic emergency presents with the very cues they are taught to associate with alcohol. The odor that ketones can produce on the breath is sometimes even mistaken for alcohol itself. Once an officer forms the belief that a driver is drunk, the field sobriety performance and the breath result tend to confirm that belief in their mind, and the genuine medical explanation never gets considered. Part of my job is to put that explanation squarely back on the table with the records to support it.
How I raise the defense
I gather your medical history and blood-sugar records, and where the breath result is in play I attack the device alongside the science, since this pairs naturally with the mouth alcohol and calibration defenses and the broader category of medical conditions that affect a DUI. A blood test, properly analyzed, often tells a very different story than the breath number, because it measures actual blood alcohol directly rather than inferring it from breath chemistry that diabetes can corrupt. See my top DUI defenses.
The records that make or break it
This defense lives on documentation. A diagnosis of diabetes, records of recent blood-sugar instability, prescriptions, and any hospital or paramedic records from the night of the arrest all help establish that a medical condition, not alcohol, drove what the officer observed. If paramedics checked your blood sugar at the scene or you were treated afterward, those records can be decisive. I move quickly to obtain and preserve them, because the closer in time the records are to the arrest, the more powerfully they show what your body was actually doing behind the wheel.
Why a blood test matters here
Because the breath machine is the part most vulnerable to the acetone problem, a blood test is often the diabetic driver's best friend. A properly drawn and analyzed blood sample measures ethanol specifically and is not thrown off by ketones the way a breath device can be. Where a breath result and a blood result diverge, that discrepancy itself is powerful evidence that the breath number was unreliable. I scrutinize which test was used, how it was conducted, and whether the chemistry of diabetes can account for an inflated reading.
It is not just for known diabetics
This defense is not limited to people who already carry a diabetes diagnosis. Undiagnosed or borderline diabetics can experience the same ketone production and the same blood-sugar swings without ever having been told they have the condition, and a stressful event like an arrest can itself push blood sugar in dangerous directions. Strict low-carbohydrate and fasting diets can also produce dietary ketosis, generating breath acetone in people who are not diabetic at all. The common thread is that the body's own chemistry, not alcohol, can drive both an inflated breath reading and impairment-like symptoms, and that possibility deserves investigation in the right case even when diabetes was never previously on anyone's radar.
How this fits the larger defense
The diabetes defense rarely stands entirely alone; it works best woven together with the other attacks on the chemical evidence and the officer's observations. The acetone problem undermines the breath result, the medical explanation undermines the field sobriety performance, and a blood test, the rising-alcohol timeline, and the calibration history all add further pressure. Presented together, they show the jury a coherent alternative story: a person experiencing a medical event who was mistaken for a drunk driver and tested on a machine that could not tell the difference. That complete picture is far more persuasive than any single point raised in isolation.
Does this fit your case? Let's talk.
Whether this applies turns on the specific facts and records of your stop, which is exactly what I review. Use the free case analysis on this page, or call me directly at (888) 271-6644. I answer my own phone, 24/7.
From the DUI blog: Arrested for DUI but You Are Diabetic: How Blood Sugar Can Mimic Intoxication.