The Los Angeles DUI Law Blog

Diets, Diabetes Can Cause False Positives for Breathalyzers

Well this is interesting. And complicated. Mostly, just complicated.

For years, the primary method of determining whether someone was under the influence while driving (besides ye ol' Sniffe the Breath Test) was to have them submit to a Breathalyzer test. In fact, most states' implied consent laws, California included, specifically require a driver to submit to either the breath test or an alternative upon demand from a law enforcement officer.

However, it seems more and more that the time-honored Breathalyzer test is less and less accurate. There are already issues when machines aren't calibrated on a regular basis. They also have a greater margin of error than a blood test. Officers are supposed to wait 15 minutes before administering it because the presence of mouth alcohol (due to a recent drink, mouthwash, or vomit) can create false positives. Now, there's even more reason to doubt the machines.

A Jamaican study, published in June 2011, found that those with Type 1 diabetes can trigger false positives when they have low blood glucose levels. The "low blood-sugar" also can make them dizzy, uncoordinated, fatigued, and imbalanced. Imagine being the cop that pulled them over. They are falling over, lethargic, and a breath test confirms your suspicions. Easy conviction, right?

Another study, done in 2007, brought attention to the story of a man in Sweden who was unable to start his car because the ignition interlock device was detecting alcohol. He was a teetotaler, so that was an impossible outcome. He was on a special ketogenic diet prescribed by his doctor.

A similar diet had a similar result for another man in 1995. He had consumed vodka the previous evening, but only in moderate amounts. His special diet also affected the reading of his blood alcohol content.

What do all of these studies have in common? All involve diets or medical conditions that increase the amount of free floating ketones in the body. Ketones are byproducts of incompletely burned fats in the liver. They are used for energy by the body's tissues. They also can be processed into Isopropanol alcohol, which causes the false positives for those on super low-carb or sub-1000 calorie diets.

What's the take-away? If you are a type-I diabetic, or are on a super restrictive diet, it's probably a better choice to go for the blood test. The ketones issues only seem to trick the Breathalyzer.

Related Resources: