To understand how residual alcohol in the mouth affects a breathalyzer reading, you first need to understand how breathalyzers work and what is “mouth alcohol”.
When you drink alcohol, your body immediately starts to absorb it in the elementary canal, starting from the mouth, the stomach all the way to the intestines. When the body starts absorbing alcohol, it starts to rapidly distribute it in the blood. When the blood reaches the liver, alcohol is filtered and removed and passed through the alveoli in the lungs. A drunk person starts exhaling some alcohol with each breath as the lungs help to exhaust the alcohol out of the body.
Enforcement officers and authorities use a device known as a breathalyzer to test the amount of exhausted alcohol to estimate the Blood Alcohol Content or BAC and determine if a person is above the allowed legal limit or not, which is set to 0.08% in all states. The handheld breathalyzers make the assumption that the air blown into the mouthpiece is coming directly from the alveoli, or deep from the lungs. This causes a problem if the person has residual alcohol in the mouth, and gives a higher than normal reading.
What is mouth alcohol?
The presence of alcohol in the mouth is the most common cause of falsely high breatalyzer readings. Common causes of mouth alcohol include recent drinking, belching, burping, hiccups and vomit. Use of dentures and the presence of dental caps or bridges may also result in mouth alcohol as it can trap it in tiny crevices in the mouth. People suffering from Gastroesophageal reflux disease or GERD may also give a higher reading as GERD causes acid reflux which releases stomach liquids into the throat and mouth. Use of certain drugs, cough medicines like NyQuil, chewing gums, mouthwashes like Listerine and breath fresheners can also give a higher reading on the breathalyzer as they contain small levels of alcohol. Therefore, law enforcement officials have to wait 15 minutes prior to testing to ensure that there is no residual mouth alcohol.
For accurate testing, it is also necessary to ensure that the subject has not consumed food or alcohol in those 15 minutes, burped, belched or vomited during that time. When conducting a breathalyzer test, certified breath-test operators have to observe the subject carefully. In the case the subject burps or belches, another 15-20 minutes have to be given before taking the test to allow mouth alcohol to dissipate. This ensures that the breath sample contains pure lung air, or as close to it as possible and is free from contaminants, including alcohol.
Using Breathalyzer Inaccuracy as argument in a DUI case
Recent studies show that breath testing is a very inaccurate method for measuring BAC in DUI cases. Although not as accurate and reliable as blood tests, breath tests are still regarded as acceptably accurate for use in DUI investigations if they are administered correctly.
Breath testing instruments have to be re-calibrated over time to maintain accuracy. Calibration is the process of checking and adjusting the accuracy of the breathalyzer by comparing its results with a known value. All handheld breathalyzers used on the roads to carry breath tests should have FDA approval. This means that the FDA tested it and approved it for use. Approvals by the DOT (Department of Transportation), NHTSA (National Highway Traffic Safety Administration) and U S Coast Guard also provide confirmation on the accuracy levels of the breathalyzer.
If you were asked to take a breath test and scored above the legal limit, which resulted in you being arrested for DUI and charged with drunk driving, your lawyer can challenge the results of the breath test. Similarly, if you have a health problem which can lead to mouth alcohol, you can discuss the issue with your DUI defense attorney who will use it in your favor in court. Defending a DUI charge is a tricky and serious matter, so you must get help from a professional and experienced DUI defense attorney to protect your rights and have the charges reduced or dismissed.