Woman checking her blood sugar levels

Can diabetes affect a breath or blood test after a DWI arrest?

By Jose Ceja
Managing Attorney

Diabetes is an extremely common disease in the United States. As of May 2024, the Center for Disease Control estimates that 38.4 million people in the United States live with diabetes. The Houston area is particularly affected by diabetes, and by some estimates, as many as 20% of Houstonians will have diabetes by 2040

With that many people suffering from diabetes, it is not uncommon for a person with diabetes to be arrested for DWI. But how does diabetes affect a DWI? Can diabetes interfere with a breath or blood test given after a DWI arrest?

Diabetes can invalidate a breath test in a DWI case

The biggest way diabetes can affect a DWI case is when a breath test is administered and is relied on by law enforcement as evidence of intoxication. This is due to technological limitations with breath testing that cannot distinguish between alcohol and certain substances present in a person with diabetes (or possibly a person in a fast or following a low-carb diet). 

The breath test machine works through a technology called infrared spectroscopy, where a beam of infrared light is passed through gasses in a breath sample to identify the type and amount of a given molecule, such as alcohol. However, due to the fact that alcohol and acetone, which is a byproduct of being in a state of ketosis due to untreated diabetes, are chemically similar, a person suffering from diabetes may have a higher reported blood alcohol content. Unfortunately, the machine used to administer breath tests in Texas – known as the Intoxilyzer 9000 – is not able to distinguish between alcohol and acetone, and this can be a real issue in DWI cases.

Although there is no known reason that diabetes could affect a blood alcohol test, a person experiencing hypoglycemia could exhibit many symptoms similar to alcohol intoxication, such as poor balance, loss of fine motor skills, flushed features, and drowsiness. These physical characteristics can also be confused with alcohol intoxication, particularly by a police officer who is determined to make a DWI arrest and is quick to interpret any behavior as evidence of intoxication.

Although most DWIs are filed as misdemeanors in the Houston area, they can be some of the most technically complex cases in Texas due to the scientific and medical issues that can come up in a case. If you believe that your diabetes had an impact on a DWI arrest, it is important that you speak with an experienced DWI attorney as soon as possible. An experienced DWI attorney should be able to tell if your diabetes played a role in your DWI and how to most effectively present that defense. Call Ceja Law Firm today for a free consultation.

About the Author
Jose Ceja is the managing attorney of Ceja Law Firm. Mr. Ceja is Board Certified in Criminal Law by the Texas Board of Legal Specialization. He has practiced law since 2007 and has devoted his career to the practice of criminal law. Mr. Ceja began his legal career as a felony drug prosecutor, where he prosecuted drug, gang, and violent offenses. Now in his career as a defense attorney, he regularly obtains dismissals, not guilty verdicts, and grand jury “no bills” in a wide variety of cases for his clients.