How Gingivitis and Periodontal Disease Affects Breath Alcohol Concentration Testings [BAC Breath]

This issue arises when someone is arrested for DUI and he or she admits to having had two or three beers, but denies feeling the effects of the alcohol. But, the breath test reflects a 0.08% or greater blood alcohol concentration. How does this happen?

It’s been known for some time now that if someone was involved in a motor vehicle accident which resulted in blood in the mouth, that the blood being breathed in the breath testing machine will cause the machine to read at a higher level. Two things need to be addressed to understand the science involved in this issue. The first issue is how does breath alcohol testing work, and issue two, how does blood in the mouth or Gingivitis and Periodontal Disease affect a blood alcohol breath test?

Issue One: How does breath alcohol testing work?

Henry’s Law is a simple law of physics that says: if you put a liquid into a sealed vacuum container with a airspace or headspace above the liquid in the container, and heat the container to 34 degrees Celsius, then the liquid within the container and the contents of the headspace above the liquid will have the same molecular makeup. However, the makeup will be in a slightly different ratio since the means of suspension, i.e., air and liquid will be different.

In breath testing they assume for each molecule of ethanol in your breath there will be 2100 molecules of ethanol in your blood, i.e., the blood is the liquid in the sealed container, and the breath in your lungs is the airspace above the liquid. Now, the breath test machine applies this ratio mathematically to each and every molecule of ethanol it detects in the breath chamber. If blood is getting into the chamber, then the blood is going to have a higher concentration of ethanol than the machine expects to see. The machine will then take the number of molecules of ethanol in the blood sample and simply multiply it by 2100.The machine will not distinguish ethanol in blood and ethanol from the lungs.

This will give a false high reading. This accompanied by the fact that most breath chambers are only taking a small sample of breath compounds the problem.

Most statutes require that a determination of the grams of alcohol, pursuant to 210 liters of breath, is what is required to have a valid breath test. For example, the common definition of a presumption of intoxication is when you have a 0.08% or greater grams of alcohol pursuant to 210 liters of breath. If you have a 0.08% or higher BAC, that triggers a presumption of intoxication.

Now, 210 liters of breath is equivalent to 55 or 56 gallons. The human lungs do not contain 55 or 56 gallons, nor was there ever a machine built that would hold 55 or 56 gallons of air. Most breath machines capture a sample, either in real time or sometimes referred to as a ‘snapshot’ sample of the breath. A typical breath chamber can be anywhere from ½ cc to approximately 60 cc’s. The machine is then going to multiply the amount of breath captured in the sample chamber by anywhere from 2,000 to 4,000 percent so that the amount being analyzed is assumed to be 210 liters of breath. The problem is compounded when you first multiply by 2,000 to 4,000 percent to get an equivalent of 210 liters of breath. Then you multiply the number of molecules of ethanol by 2100.

If blood gets into the breath machine along with the breath, you can have a staggering result of a 0.15 to 0.18 BAC, and in fact the individual could be well below a .08 BAC at the time of driving. This is all a result of the mathematical process that goes on within the breath machine and when the machine is reading molecules of ethanol in blood and assuming that it is molecules of ethanol in air.

Issue Two: How does blood get into the mouth?

It has been known for some time, that when you have some kind of automobile accident or any other traumatic injury to the mouth, there can be blood in the mouth which would affect breath alcohol testing.

What I have been working on and developing with one of my expert witnesses is the affect of Gingivitis and Periodontal Disease in breath testing. Gingivitis can simply be defined as “bleeding gums”. The actual cause of this condition has to do with bacteria and plaque which buildup around the teeth. This causes the gum area around the teeth to become sensitive and will bleed. A lot of people do not take proper case of their teeth, and constantly experience blood in their mouth when brushing their teeth. One question I ask my clients is if when they brush their teeth or floss their whether or not they get blood in their mouth. Or when they spit out toothpaste, is there blood mixed with the toothpaste. If the answer is yes, you now have a serious issue that is going to affect the accuracy of breath alcohol testing.

The next area to be addressed is Periodontal Disease. Periodontal Disease results in periodontal pockets that are nothing more than a depression or pocket that develop next to the teeth where the bacteria next to the teeth has been eating away and creating small areas or pockets where blood and alcohol can be stored in the mouth. In these pockets, alcohol, food and blood can get trapped, so that when you perform a breath test, you are breathing food particles, along with blood and alcohol into the breath testing machine.

What needs to be understood and clearly spelled out, is that the Gingivitis and the accompanying bleeding problems associated with Gingivitis is a continuing process. Most breath testing procedures require a fifteen minute observation period of the subject prior to the subject breathing into the breath machine. This procedure is supposed to allow the evaporation of any potential mouth alcohol. When you have Gingivitis, it is a continuing and ongoing process. There is nothing the subject can do to stop the bleeding process, it is occurring the subject’s mouth. You can rinse your mouth out or wait all the time you want, but nothing is going to stop the bleeding of the gums. It is, as I stated, continuous. There is nothing anyone can do to stop this bleeding process. [Potentially seeing a Dentist and getting treatment for the condition can help.] In fact, according to my experts, the trauma to the gums of putting your lips around a mouthpiece and blowing into a breath testing device will in all probability increase the amount of blood getting to the breath testing machine, as it is causing more trauma to the gums that are already bleeding.

The two leading articles in this area are A Simulation of the Affect of Blood in the Mouth on Breath Alcohol Concentration of Drinking Subjects, by J.G. Wigmore and M. P. Wilke, published in Canadian Society of Forensic Science Journal, Volume 35, Number 1 (2002) pages 9-16. The other article is The Affect of Blood in the Oral Cavity on Breath Alcohol Analysis, by M. Chu, D. L. N. Wells, R. G. King, J. Farar and O. H. Drummer, published in the Journal of Clinical Forensic Medicine (1998) Volume 5, pages 114-118.

These two leading articles on blood in the mouth are helpful. In the Wigmore and Wilke article, the subjects even held blood in their mouths, then spit the blood out, waited ten minutes, then took a breath test. Their conclusion was that there was no significant affect of blood in the mouth. This was based upon the blood being spit out and a minimum ten minute observation period. This is clearly different than the theory being proposed here, inasmuch as the gums are continuously bleeding and it stays in the mouth, you cannot get rid of it.

In the other article entitled, The Affect of Blood in the Oral Cavity on Breath Alcohol Analysis, the results were quite significant for the defense. The test was broken into four stages, Stage A, B, C, and D. Stage A was a breath test before solution was put in the mouth. Stage B was with solution in the mouth. Stage C was with solution in the mouth. And Stage D was a test after the mouth was rinsed.

In all of the groups tested, during Stages B and C, WITH SOLUTION IN THE MOUTH a statistically significant increase in BAC was found. This would confirm that blood in the mouth through Gingivitis and potentially through Periodontal Disease causes a continuous bleeding in the mouth and there is nothing that can be done to prevent the contamination of the test and of the test giving a false high reading of the subject’s Breath Alcohol Concentration.