If you are pulled over on suspicion of drinking while driving, you may be asked to take a roadside breath test. Law enforcement officers in Ohio and in other parts of the United States often use breath tests to determine whether someone is driving with an alcohol level that is above the legal limit. The problem lies in the fact that roadside breath tests may not always give an accurate representation of one’s blood alcohol content level. This misreading may cause a person to be wrongfully charged with drinking and driving, even when their BAC level is below the legal limit.

Although breath test devices are designed to measure the amount of ethyl alcohol in the blood, other substances, such as residual blood, food, drinks and vomit, that are left in a person’s mouth may alter the reading. Other substances found in the environment, including gas fumes, pollution and paint fumes can affect a person’s reading as well. The temperature and relative humidity of the air can alter the breath test device’s ability to make accurate readings, if the machine has not been calibrated to operate in these specific environments.

Another problem with breath test devices it that the amount of alcohol found in a person’s breath may not accurately represent their blood alcohol level. According to the State University of New York at Potsdam, breath tests may vary by as much as 15 percent when compared to the results of a person’s BAC level obtained through a blood test.

This information is intended to educate and should not be taken as legal advice.