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How to Avoid a False Positive on Breath Alcohol Ignition Interlock Devices

Sep 8th, 2016 Breath Testing

Michigan drivers arrested or convicted of drunk driving might be ordered to have a Breath Alcohol Ignition Interlock Device (BAIID) installed on their car. Some judges will require a BAIID to be installed as a condition of bond.  Other times, a BAIID can be a condition of probation. With a high BAC case (test result at or above .17) a BAIID will be a condition of obtaining a license.  Repeat offenders suffering from license revocation will be required to have a BAIID installed as a condition of later obtaining driving privileges. Sobriety courts also use BAIIDs as part of their programs.

In each of these instances, a positive alcohol test on the BAIID will result in serious consequences, ranging anywhere from jail time to additional license sanctions.  A frequent question then is how does one avoid a false positive.  That is, if you have a BAIID on your car, how can you avoid having a false positive reported to the court?

The best and most obvious way to avoid a “false” positive is to not drink. Sometimes a person who is ordered to stop using alcohol, but who knows when they will be tested, tries to outsmart the system by drinking only a little and hoping that when they are testing, the alcohol will have left their body.  This idea is not only wrong; it’s doomed to fail.

However, even people who maintain complete abstinence from alcohol can sometimes find themselves faced with a false positive alcohol BAIID result. Though rare, false positives are possible because BAIIDs use fuel cell detectors to detect and measure alcohol.  Simply stated, fuel cells, like those found in PBTs and BAIIDs, have metal in them that reacts in the presence of ethanol, which is beverage alcohol.  The reaction produces ions which produce an electric charge, that can then be measured. Trouble is, the metal in fuel cells can also give off ions when exposed to other chemicals.  Since a fuel cell can’t tell what’s causing the ions to be released, it “assumes” the ions are from beverage alcohol.

For example, one study reported in the Journal of Analytical Toxicology showed that energy drinks can cause false positives.  Looking at this study, it is clear that popular drinks like Monster and Rock Star can cause false positives!  These can be as high as .015.

Mind you, .015 is very low so we are not talking about levels of intoxication, such as .08 or above, but even these very low levels can be enough to cause serious problems in some courts.  For example, in Michigan’s 52-3 District Court in Rochester Michigan, the court requires that all readings be reported, not matter how small.  These very low levels can then trigger a bond or probation violation hearing, that can then result in jail time.

A different study by A.W. Jones found that inside the body Acetone can be converted to isopropanol that can then give similar false positives.  (Case report: Biotransformation of Acetone to Isopropanol Observed in Motorists Involved in a Sobriety Check).

And in another article co-authored by Dr. Michael Hlastala and Patrick Barone, it is indicated that things like methyl alcohol and antifreeze can give false positive results. (see Hlastala, Barone Identification of Transdermal Ethyl Alcohol, DWI Journal, Law & Science, vol. 22, no. 11 (2007).

If you are ordered by a judge to have a BAIID installed on your car, then be sure to be ultra-cautious to avoid anything, including body washes, hair sprays, non-alcohol drinks, etc., that may have any ability to cause a false positive.  Most of all, don’t drink any alcohol at any time while the BAIID is on your car.