Can Medical Conditions Affect DUI Test Results?

Yes, and it happens more often than most people realize. Certain medical conditions can mimic the signs of intoxication, produce false-positive readings on chemical tests, and cause you to fail field sobriety evaluations even when completely sober. If a health condition contributed to unreliable test results, it may be possible to challenge DUI charges on that basis.

Field Sobriety Test (FST) Challenges

Standardized field sobriety tests measure balance, coordination, and eye movement, but dozens of medical conditions can compromise your ability to perform these tasks regardless of alcohol consumption. Inner ear disorders, neurological conditions like multiple sclerosis or peripheral neuropathy, back and knee injuries, and even certain medications can cause the same unsteady gait, poor balance, and involuntary eye movements that officers interpret as signs of impairment.

Breathalyzer and Blood Test Issues

Chemical testing equipment is not infallible, and certain medical conditions can produce readings that suggest intoxication when no alcohol has been consumed. Conditions that may generate false-positive breathalyzer results include the following:

• Gastroesophageal reflux disease (GERD)
• Diabetes
• Chronic obstructive pulmonary disease (COPD)
• Hypoglycemia
• Dental work or oral conditions

Blood tests carry their own vulnerabilities. Contamination during the draw, improper storage of samples, and fermentation of blood in the vial can all produce elevated BAC readings that do not accurately represent your level of impairment at the time of the stop.

What Are the Legal Implications?

Under Tennessee Code Annotated § 55-10-408, chemical tests in DUI cases must follow specific legal procedures. Any failure to comply with those requirements, or evidence that a medical condition affected the results, can undermine the reliability of the test and weaken the prosecution’s case.

Proving a Medical Condition Affected DUI Test Results

Building a medical defense requires more than claiming a health issue exists. You need documented evidence linking your condition to the specific test failures the prosecution plans to use against you:

• Medical records confirming a diagnosed condition
• Testimony from treating physicians or medical specialists
• Independent analysis of breathalyzer or blood test results
• Documentation of medications and their known side effects
• Officer bodycam footage showing physical symptoms consistent with a medical episode

The stronger the connection between your diagnosis and the flawed results, the more difficult it becomes for prosecutors to rely on that evidence at trial.

Medical Conditions Can Be a Legitimate Defense in DUI Cases

Our attorneys at Andrew C. Beasley, PLLC, investigate every aspect of the testing process and your medical background to determine whether a health condition compromised the accuracy of the results used against you. We obtain your medical records, consult with physicians and toxicology specialists, and present evidence showing that the prosecution’s chemical test results are unreliable.

Call us at 615-846-9889 or reach out online to schedule your free consultation with our DUI lawyers in Nashville, who can evaluate your medical history alongside the arrest details and determine whether a medical defense gives your case the strongest path to a favorable outcome.