Law officers in Minnesota and throughout the United States often use breath test devices as a way to determine whether someone is driving while intoxicated. Drivers who have a blood alcohol content level of 0.08 or higher can be arrested and charged with a DUI in Minnesota.
However, studies show that breath test devices do not always yield accurate and reliable results. In some cases, breath test machines give elevated readings which could lead to a wrongful DUI arrest.
How do breath test devices work?
Breath test machines measure the amount of ethanol alcohol present in an exhaled breath sample. The device then converts this amount to a blood alcohol content level. According to the State University of New York at Potsdam, breath test readings can vary by more than 15% from the results from actual blood tests.
This is due to the fact that machines pick up more than just ethanol alcohol in the exhaled breath sample. They read other methyl structures that can be found in other substances.
What factors can alter breath test results?
Factors that can affect breath test device readings include the following:
- Residual food, blood, vomit or drink in the mouth
- Tobacco smoke
- Dirt, pollution and fumes in the air
- Relative humidity and temperature of the air
- Electrical interference from police radios and cellphones
- Inhaled fumes from gasoline, paint or paint thinner
Breath test devices must be calibrated properly and regularly in order to work correctly. Furthermore, officers must be trained on how to use the devices properly to maximize the accuracy of results.