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What Affects a PAS Test (Breath Test)?

Breath tests are the most common chemical test administered for DUI investigations because they can be used roadside and the results are instantaneous.

This type of test has both pros and cons.

The pros are that you immediately know what your alcohol level is and whether you will be arrested or not. The cons are that the results are immediately known and the officer has solid proof that you may be over the limit.

When the officer knows you are over the limit, it is possible that his arrest report will be skewed. For example, if you sway a couple of inches in a field sobriety test (FST), he will most definitely note it in his arrest narrative if he already knows you are above .08. If he doesn't know, the minor sway is actually quite normal for anyone in a stressful situation such as a DUI investigation and may not be noted in his report.

There are numerous myths about what may affect a breath test. Some are true, some are false, and some are a factor but to such a minor degree that it may not really matter.

Here are some factors that may affect a breath sample which are described below:

  • mouth alcohol
  • mouth piercings
  • acid reflux
  • diabetes
  • dentures
  • dental work
  • some foods.

Prior to performing a breath test, the officer must have continuous observation of you for 15 minutes. This is to ensure you don't burp, vomit, chew gum, eat, smoke, or put anything in your mouth. After this period, it is assumed that you have no "mouth alcohol" lingering in your mouth. Mouth alcohol is basically alcohol-enriched gas deposited in your mouth. So if you burp, you may have brought up some alcohol rich gas into your mouth that would make a breath test read high.

Mouth piercings, dentures, and dental work may affect a PAS reading because alcohol can be trapped. This is not likely to win at trial since an expert must perform breath testing on you showing how much it affected your test, and then have the scientific background to testify in court and convince a jury.

Acid reflux (GERD) is a condition where acidic liquid in the stomach comes up to your mouth via the esophagus. This is similar to a burp in which alcohol from the stomach is now mouth alcohol. For this defense to work, there must be a documented medical history of acid reflux.

Some diabetics may test positive for acetone, isopropanol, and ethanol (alcohol) even if they have not consumed alcohol, or may enhance the actual alcohol detected in the breath. However, the mobile breath machines are able to detect and differentiate between diabetic and alcohol positives.

Some foods such as bread, soy sauce, soft drinks may register slightly on a breath machine. However, this is generally a weak defense and unless it can be scientifically proven and demonstrated to the courts that this was a factor in your case (must do experiments).

That being said, at Wilfert Law, our attorneys have the experience to not only recognize these defense but to fully exploit them if they are a factor in your case. We have decades of experience in DUI defense and breath test evidence. If you find yourself needing experienced defense, call the office for a free consultation. 805-324-6777