Ketogenic Diets or Diabetes Breathalyzer False Positive


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Tag Archives: false positive

Ketogenic Diets or Diabetes Breathalyzer False Positive

Ketogenic Diets or Diabetes Breathalyzer False Positive.

Was the breathalyzer in my DUI case operating properly?
Persons that are on ketogenic diets, or in ketosis due to high protein low carb diets can have false positives. Also, diabetics experiencing ketoacidosis may produce endogenous acetone, which may even, in turn, metabolize into ispropanol alcohol. Ketogenic Diets or Diabetes Breathalyzer False Positive is a problem.
Breath testing devices might better be characterized as relatively specific for detecting ethanol, as practically applied in breath tests of live human subjects.
Consider three types of alcohol breath instruments :


 The cheapest portable breath testers (PBTs) and some ignition interlock devices use semiconductor technology. These are likely the kind you might buy at Radio Shack as a novelty. I believe that these devices can’t quickly-enough-for-an-instant-test distinguish between ethyl (drinking) alcohol and its chemical cousins, such as isopropyl alcohol, methyl alcohol, toluene, and maybe acetone (which is a keytone). Such a PBT may indiscriminately and cumulatively measure ethyl alcohol and its cousins, if present.
Therefore, a cousin of ethyl alcohol could, by itself, be the source of a false positive for ethyl alcohol. Further, it could be combined with any present ethyl alcohol to result in anelevated positive.


 More expensive PBTs use fuel cell technology. These are the kind that law enforcement is likely to use in the field. An example of a fuel cell PBT is the Intoxilyzer SD-5. Its operator’s manual at page 23 under “specificity,” declares: “The detector is unaffected by acetone, paint and glue fumes, foods, confectionery, methane, and practically all other non-alcoholic substances at the levels found in human breath.” (Emphasis added.)
Granted, this is a disclaimer by a very interested party, the manufacturer.  But note that it doesn’t claim total specificity.
At the very least, fuel cells are relatively specific to ethyl (drinking) alcohol. While fuel cells may react to non-ethyl alcohols, perhaps even those such as acetone found in human breath, they do so at a slower rate, according to Hansueli Ryser, executive director of Draeger Safety Diagnostics Inc., a manufacturer of breath-testing devices.
Perhaps that reaction is too slow (or too slight) to make any practical difference in an instantaneous reading.  Perhaps to register, the amount of the interferant cousin of ethanol must be so high that it couldn’t exist on the breath of a living, breathing human.
The science, and the machines, don’t know where to place sorbitol or xylitol as a sugar alcohol which can create a false positive in the spectrum of the alcohol family.


 Modern evidential breath-testing machines, such as the type used in Orange County DUI breath cases, employing infrared spectroscopy with chopper wheels and/or pulsing light sources, can allow them to distinguish ethyl alcohol from potential interferants, its chemical cousins.
Perhaps an exception would be where the ethanol reading may be slightly elevated because of a false positive vector from isopropanol.

Sugar Alcohol: is it a Breathalyzer False Positive?

Sugar Alcohol: is it a breathalyzer false positive?

dui breath test
Sugar Alcohol: is it a breathalyzer false positive? As Orange County DUI Attorneys, we are often asked about what can be a false positive for breathalyzer testing.  Is It’s not surprising that any mouth alcohol–that is, ethanol or any of its chemical cousins — can be detected.  For that reason, the breath testing laws require an appropriate waiting period prior to the breath sample.
The main issue can be referred to as the various instruments’ capabilities for specificity.  That is, can it measure the specific kind of alcohol–ethanol for the purposes of testing in a DUI case –to the exclusion of any false positives for ethanol?

Sorbitol and false positives

Sorbitol is a sugar alcohol with a sweet taste which the human body metabolizes slowly.  It is used in mints, gums, toothpaste, and many sugar-free products.  Sugar alcohol is generally part of the chemical composition of sorbitol and xylitol, which is both one of many forms of alcohol derived from fruit.

Those substances are used as a sugar replacement due to its sweet characteristic in gum, food and other general consumer products.  It is slowly metabolized by the body, so DUI false positive effects for diabetics and glucose (or insulin) are minimal to none.

The problem is that all of the following are alcohol, only in different forms:

  • Ethyl alcohol;
  • Isopropyl alcohol;
  • Methanol;
  • Ethanol alcohol;
  • Glycol alcohol;
  • Sorbitol (sugar alcohol); and
  • Xylitol. 

Each will test positive for alcohol as measured by a testing device.  Breathalyzers, or any breath testing machines, that use Fuel Cell technology are well documented not to be specifically able to measure only ethyl alcohol in readings. And as our Orange County DUI Lawyer Robert Miller can tell you, ethyl alcohol is the only relevant type of alcohol to be tested in the machine for a DUI.

Sorbitol and Breath Testing

Anecdotally, many in the breath testing industry confirm that blowing into breath testing machines with sorbitol in the mouth will cause false positives.  A machine can falsely read as high as .04 for alcohol (when you are actually 0.00%) when chewing sorbitol gum or mints.

A television news crew, reporting on a DUI case that ended up being dismissed in Massachusetts, used Crest toothpaste, which contains sorbitol, and a lozenge, on a subject that had no alcohol.  The toothpaste resulted in a .04% reading on a breath testing device in that state that had read a 0.0% before the test. When repeated with the lozenge, the same result occurred.

It is not unusual for persons that have been drinking, and many that are not drinking, to have mints in their mouth with sorbitol when they are stopped by the police. As a result, the most common scenario is for the false positive reading for sugar alcohol to be added to any alcohol found in the breath, making the reading artificially high, and usually above the legal limit of a .08% alcohol level.

As with false positives for acetones, sugar alcohol can be a false positive for alcohol.  An expert witness experienced in the field of alcohol can help explain false positive breath tests to a jury and get a not guilty at trial in a DUI case.  That is done by explaining the science of how the sugar alcohol inflated the reading.

Sorbitol in the Blood as a False Positive for Alcohol

Blood sorbitol, as opposed to mouth sorbitol, is tested slightly differently.  The question for any blood test where sorbitol is involved is whether or not its presence in the bloodstream will register as ethyl alcohol on any breath machine or specifically on a breath testing device.  Those machines will typically register any alcohol in the body, including “sugar alcohol”,  even though there is no evidence that sugar alcohol makes someone drunk.

It is always a good idea in every case to talk to an alcohol expert experienced in DUI cases on the subject.  Because most breath machines can’t tell the difference between the alcohols, any sugar alcohol combined with any existing ethyl alcohol molecules will combine together, to give an artificially inflated higher reading. That can be a problem if someone was, say, a .06%, but the sugar alcohol issue tests at a .04% (as it did in the tests above).  The reading would be a .10%, putting the subject above the .08% level, even though they were actually below the legal limit.

When it comes to blood testing defenses, an expert witness will think of overlapping peaks (the alcohol curve of the sugar alcohol, plus the alcohol curve of the drinking ethyl alcohol), as an additive effect, which under what may appear to be a single peak to a more unsophisticated testing machine.

Sugar Alcohol: is it a breathalyzer false positive? How Alcohol Testing Works

Devices that use a fuel cell to measure the alcohol generally detect all alcohols that are present in the breath.  A fuel cell oxidizes the alcohol molecule in a chemical reaction.  If the alcohol would burn if a fire was applied, in general, it will react in the fuel cell.  Burning is a process of oxidizing a substance, and you know that if we remove all of the oxygen, a fire goes out.  Fuel cell machines (like the breathalyzers used in Orange County DUI cases) assume that if alcohol is reported, it only is reporting ethanol.  Sometimes that assumption is wrong.

Machines that use an infrared detection method rely upon the molecular vibrations that occur between different parts of the alcohol molecule.  For example, the Intox 8000 and 9000 depend on the vibrations that take place between the “O-H” hydroxyl portion of the molecule and the rest of the alcohol molecule.  They do this with the 9.5-micron filter they employ.  Since all alcohols have this “O-H” hydroxyl component, all of the alcohols will be reported by this measurement technique.  The analysis is very machine dependent.

There is no known or generally accepted extrapolation formula to determine the increase of the breath alcohol test result from sorbitol, xylitol etc.  The best practice is to use whole blood analysis with proper Gas Chromatograph testing.

How much of an increase from any in the blood?  That is related to, and the key issue, in a sugar alcohol false positive case. But it is in most cases unknown. In a DUI cases, it may help to show reasonable doubt to introduce this as evidence in the case.

How to Present Alcohol False Positive Information in a DUI case.

Understand that it remains the government’s burden to prove a DUI case beyond a reasonable doubt.  All the DUI defense attorney needs to do is to show problems or holes in the proof offered by the prosecutor.
The key is that it can be a significant error, and the government does not know how much higher it could have caused the reading to be either.  There is no published literature on the topic, regarding sorbitol in particular.  The mechanics of how the devices work leaves little doubt that they cannot discriminate between the different forms of alcohol, and that these forms of alcohol can be in the breath.  Trying to develop a formula for how much the result is off by is a dangerous undertaking — and usually, it is not possible, given all of the variables.
In breath testing science, you either can state that the measurement is correct or you cannot say that.  If it can be incorrect, because of any reason, including the introduction of other forms of alcohol, then you cannot trust the answer.

Contact Us For Questions.

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Sugar Alcohol: is it a breathalyzer false positive? If you have questions about the effect of sorbitol or sugar alcohols like xylitol or sorbitol on DUI breath testing machines, contact our office for a free consultation.  We are here to help.
With impeccable credentials, hundreds of great results in DUI cases, and over 22 years of courtroom and trial experience, Robert Miller is the right choice for any case where you need the help of our DUI attorneys.