Yes. Medical conditions can materially affect Illinois breathalyzer results. GERD and hiatal hernia allow stomach alcohol to reflux into the mouth during the exhalation, producing mouth alcohol contamination that overstates BAC. Diabetic ketoacidosis produces acetone the machine may misread. Recent dental work, oral piercings, and dentures can trap alcohol. Asthma and COPD affect the ability to deliver an adequate sample, and repeated failed attempts can be scored as refusal. Certain medications and diets producing ketones create similar interference. Under Illinois evidentiary standards the state does not have to affirmatively rule these out, but a documented medical history creates reasonable doubt. A Chicago DUI lawyer builds the medical record into the defense.
