Intoxilyzers and Other Infrared Breath Testing Machines Have Similar Problems
A major issue with infrared breath testing devices is that they not only detect the ethyl alcohol found in alcoholic beverages but also in other substances that have a similar molecular structure. Stated differently, these devices identify any compound containing the methyl group molecular structure. And the issue with this is that more than one hundred compounds can be found in a human's breath at any one time and 70% to 80% of these compounds contain the methyl group molecular structure. The consequence of this is that these methyl group molecular structures will be incorrectly identified and labeled as ethyl alcohol. Interestingly, the more ethyl group substances the breathalyzer detects, the higher the false blood alcohol content estimate will be.
Acetone and other Ketones Confused with Alcohol
The National Highway Traffic Safety Administration (NHTSA) has found that people who are diabetics or dieters can have acetone levels that are hundreds, if not a thousand of times higher than people who are not diabetics. Acetone interferent detection levels on breath testing machines are set at fatal levels, so the amount a human might actually have on his/her breath will not usually be detected as acetone by the machine but will be read as alcohol. The same is true of other ketones commonly found on the human breath.