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Questioning the accuracy of breath test devices

Breath tests and blood tests are both used to determine the amount of alcohol in a driver’s system. Yet, breath tests may not be accurate indicators of intoxication.

Law enforcement officers in Idaho must have probable cause to stop a driver and subject him or her to a breath test. Officers often use these roadside tests to help determine whether a driver's blood alcohol content level is above the legal limit of 0.08 percent. If a driver's breath test indicates that they are intoxicated, he or she may be arrested and charged with a DUI. Studies show, however, that many breath test devices render inaccurate results. These unreliable machines could, in some cases, lead to wrongful DUI charges.

Blood alcohol content vs. breath alcohol content

Blood tests have generally been recognized as the most accurate way to determine how much alcohol is in a person's system. Rather than measure the BAC level directly through a blood sample, breath test machines calculate the amount of ethanol alcohol present in a person's exhaled breath. The device then converts the measurement to a blood alcohol content level. The variances between blood tests and breath test results, however, show that these tests may be incomparable to one another. The State University of New York at Potsdam reported that nearly one in four drivers who take a breath test will have higher BAC results when compared to an actual blood test reading.

Factors leading to inflated breath test results

There are many factors that contribute to breath test device inaccuracies and can alter the results. These include:

• The relative humidity and temperature of the air

• The concentration of pollutants and dirt in the air

• Any residual food, vomit or blood in the subject's mouth

• Whether the driver was exposed to tobacco smoke, gasoline fumes, paint fumes or other cleaning fumes

• Electrical interference from officers' radios, cellphones and other electronic devices

• Physiological differences in the way people metabolize alcohol

SUNY also states that breath test results can vary depending on the subject's hematocrit levels, or the amount of cell volume in the blood. The hematocrit level is taken into account when testing a driver's breath alcohol content level. Yet some people naturally have a lower hematocrit level, which may increase their BAC readings substantially. Furthermore, breath test machines must be calibrated regularly and used properly in order to increase the accuracy of the results.

Dealing with the consequences of a DUI

A DUI can have heavy consequences on many areas of your life. You may have trouble qualifying for a professional license, finding a job in some career fields and regaining control of your driving privileges. It may help to speak with a defense attorney who knows how to handle DUI cases in Idaho. A lawyer may be helpful in looking over the details of the incident and seeing whether your case was handled properly.

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