Nearly 50 Years of Fighting for Clients in Need SET UP YOUR FREE CONSULTATION

The Relationship Between Ketones and Roadside Breath Tests

The Law Office of Joel M. Bacher Oct. 29, 2020


Are you one of the millions of people across the country, including many here in New Jersey, who live with diabetes? Do you follow the Keto diet? If you answer yes to one or both of these questions, you could end up under arrest for drunk driving even if you haven’t had a drink.

Why? Because roadside breath testing machines could mistake the ketones in your body for alcohol. If this happens, the officer administering the test may place you under arrest. Fortunately, you will have the chance to clear your name with a blood test or the evidentiary breath test usually given with a much more precise machine, but the damage may already be there.

Understanding how Breath Tests Calculate Blood Alcohol Concentration

When you drink alcohol, it absorbs into your blood stream and reaches its highest concentration in your body within minutes to an hour, depending on a variety of factors individual to you. From there, your liver goes to work breaking down the bulk of the alcohol since this organ’s job is to eliminate toxins from the body. If you continue drinking alcohol before your body can metabolize it, your liver simply can’t keep up.

The other 10% or so of the alcohol in your system leaves your body through your breath and urine. When you take a breath test, it calculates how much alcohol leaves your body through your lungs, i.e., your breath. Sounds reasonable, but there are some issues with this process.

Understanding how Ketones Affect Roadside Breath Tests

If you suffer from diabetes or follow the Ketogenic diet or another low-carb diet, your body produces higher levels of ketones than people without this condition or on other diets. Acetone is a component of ketones, and when metabolized, it could produce hepatic alcohol dehydrogenase in your body. Ordinarily, this wouldn’t be a problem, but if a police officer pulls you over on suspicion of drunk driving and you take a roadside breath test, it could give a false positive for intoxication because of the acetone levels in your breath.

If this happens to you and you end up under arrest, you need to take the situation seriously. Even though further testing may clear you of drunk driving, it is still up to you to protect your rights. Even having an arrest for DUI on your record could have adverse effects on your future. Exercising your right to counsel immediately could help keep that from happening.