Breathalyzer results for diabetics could read higher than actual BAC estimates because, according to the NHTSA (National Highway and Traffic Safety Association), these individuals can have high levels of acetone in their breath. The same goes for individuals on extreme diets including fasting and low carb diets.
Acetone is a substance that is falsely identified as ethanol (also called ethyl alcohol) by some breath alcohol testers—some semiconductor sensor-based breathalyzers will show a false positive result for these cases when the test subject has not consumed alcohol.
However, whether or not the presence of acetone will affect a breathalyzer reading depends on the actual breathalyzer used for testing. Breathalyzers with fuel cell sensor technology, such as the BACtrack Mobile, BACtrack S80 Pro, BACtrack S75 Pro, and the BACtrack Element are all non-responsive to acetone, and therefore won’t show a false positive for someone who is diabetic, or on a high protein/carbohydrate-restricted diet.