The breath test unreliability factor

Although officers use breath test devices to determine BAC levels, these tests may not always provide accurate results.

When people are pulled over on suspicion of drunk driving in Tennessee, they may be asked to take a roadside breath test. Law enforcement officers use the results of these tests to determine whether a motorist is over the legal intoxication limit of 0.08 percent. People who have a blood alcohol content that is at or above the legal limit may be arrested, charged and possibly convicted of a DUI. Studies show, however, that the results from breath test devices are not completely accurate and the unreliable readings they give may lead to wrongful DUI arrests.

Blood tests vs breath tests

Instead of measuring the actual amount of alcohol that is in the blood by taking a blood sample, breath tests determine the amount of ethanol alcohol that is in an exhaled breath sample and then convert that amount to a BAC level reading. When the results of an actual blood test are compared to a breath test, significant discrepancies are often found. Research from the State University of New York at Potsdam report that the tests can vary by at least 15 percent. That means that one in every four people who use a breath test will show inflated results.

Factors leading to false breath test readings

There are several factors that may account for these differences. People who have certain medical conditions, such as diabetes, may have inflated test results. Any residual food, drink, blood or vomit that is in a person's mouth can affect the amount of alcohol that is read in the breath sample. In some cases, structures that naturally occur in peoples' saliva can influence the results.

Other factors in the environment can inflate breath test readings, including the following:

· Fumes from gasoline, tobacco smoke, cleaners, paint and paint removers.

· The relative humidity and temperature of the air.

· Interference from law enforcement radios and cellular devices.

Furthermore, if officers fail to calibrate the device regularly and properly, the results can be distorted.

Seeking legal help

People who are convicted of a DUI in Tennessee face serious penalties, including fines, driver's license revocation and possible jail time. In addition, people who have a DUI on their record may be unable to find employment in certain industries, obtain a professional license or be approved for financing. If you face DUI charges, you may want to contact a criminal defense attorney who may be able to help answer your questions. An attorney may be helpful in exploring your legal options, and putting you on the path to recovery.