Tennessee DUI Defense Lawyer
Law Offices Of
James A.H. Bell, P.C.
865.637.2900
The Law Offices Of James A.H. Bell , P.C. represents clients in the cities and counties of Athens | Chattanooga | Cleveland | Cookeville | Crossville | Gatlinburg | Greeneville | Jefferson City | Kingston | Knoxville | Maynardville | Memphis | Nashville | Newport | Pigeon Forge Sevierville and the tri-cities of Kingsport | Johnson City and Bristol | Knox County | Anderson County | Bledsoe County | Blount County | Bradley County | Campbell County | Carter County | Claiborne County | Cocke County | Cumberland County | Davidson County | Franklin County | Fentress County | Grainger County | Greene County | Hamblen County | Hamilton County | Jefferson County | Johnson County | Loudon County | McMinn County | Marion County | Meigs County | Morgan County | Polk County | Putnam County | Rhea County | Roane County | Scott County | Sequatchie County | Sevier County | Union County | Warren County | Washington County.
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DUI Breath Test
The determination of the blood alcohol concentration, or BAC, is an important part of the State’s case in a DUI prosecution. As we read in the section about the DUI blood test, BAC refers to the measurement of milligrams of alcohol contained in 100 milliters of blood. Usually expressed as a percentage, the BAC can be generally thought of as equaling one drop of alcohol for every 1000 drops of blood. In this case, the BAC would be expressed as 0.10. The higher the BAC number the more impaired a person is by law. As we also saw while reading about the blood test, an officer who has arrested a person for DUI has the option of asking that person to take either a blood or breath test to determine BAC. Although most people think of a BAC measured from the blood as the same as that obtained from breath by a breathalyzer, there is an important difference. A breathalyzer doesn’t actually read a person’s BAC, it estimates it. Breathalyzer results can be far from 100% accurate, and many aspects of the breath test may be subject to legal challenge.
The term “breathalyzer” has come to be a generic reference to any instrument used to determine the amount of alcohol in a person’s blood by analysis of that person’s breath. More accurately, Breathalyzer was the brand name of a series of breath analyzing products manufactured by Smith and Wesson in the late 1950s. Today, there are dozens of breathalyzer instruments, and their design and performance is subject to highly prescribed regulations. The principle by which a breathalyzer works involves measuring the concentration of alcohol in the air a person exhales. The ratio of alcohol concentration in exhaled air in relation to the concentration in the blood is approximately 2,100:1. This means that 2,100 milliters of exhaled air will contain an identical amount of alcohol as 1 milliliter of blood. In actuality, this ratio may range between 1,700:1, and 2,400:1. Put into practical terms this variance means that a breathalyzer BAC reading of .08 could actually be a BAC of between .065, and .09. Such a variance could mean a huge difference in a DUI case.
The problems with breathalyzers do not end with the variance in BAC measurement. The device itself may be confused by other substances. A breathalyzer tests for ethyl alcohol, or ethanol, from alcoholic substances. The breathalyzer may misread other substances in the human breath as alcohol content. For example, a breathalyzer may become confused by acetone, which may be present in large amounts in people with diabetes and those with special diets.
In addition, the BAC measurement from a breathalyzer may also be affected by an individual’s body temperature and blood composition. Individuals with reduced blood content may show an artificially high BAC reading. Vomit or blood in the mouth can skew breathalyzer readings on the high side. It is also important to realize that since the presence of alcohol in the bloodstream – and thus in the lungs – lags consumption by several minutes, the breathalyzer can
produce an aberrantly high BAC due to the presence of alcohol actually in the mouth. For this reason a police officer is required to observe a person for at least twenty minutes before the breathalyzer test is administered to be certain that the person being tested does not vomit, belch, or otherwise regurgitate stomach fluids. A failure of the officer to actually observe the person for twenty minutes before the test is administered will legally invalidate the results of the breathalyzer test.
Breathalyzers are also subject to circuitry problems and Radio Frequency Interference, or RFI, from devices such as cell phones and police radios. Such RFI can result in inaccurately high BAC readings. Other factors that can affect breathalyzer accuracy and validity include: recent environmental exposure to volatile fumes such as lacquer, gasoline, paint, adhesives, dry cleaning fluids and even Formula 409; physical problems such as gastric reflux, hiatal hernia, GERD, IBS, or acid reflux; dental conditions such as gum disease and gingivitis, or dentures and bridgework which can trap pockets of alcohol and contaminate a breathalyzer sample; and finally physical limitations such as asthma bronchitis, emphysema, and COPD which can limit the amount of air a person is able to produce for testing.
While the list of potential legal evidentiary problems with a BAC measurement produced by a breathalyzer may not be endless, it is extensive. The burden is always on the prosecution to prove that a person is guilty of a crime. In order to meet that burden, only validly obtained and reliable evidence can be used. At the Law Offices of James A. H. Bell, P.C., we have lectured to national bar groups on the subject of both blood and breath testing of BAC. Moreover, we have aggressively litigated these and other legal issues relating to the collection, preservation, and testing of blood and breath for alcohol content. We are familiar with the issues, we are knowledgeable in the law, and we have the experience to help you get the best result possible in your case.