Do breath test devices give accurate BAC level readings?

Do breath test devices give accurate BAC level readings?

On Behalf of | Feb 8, 2021 | DWI Charges |

Getting pulled over by a law enforcement officer in Louisiana is not for the faint of heart, especially if it is on suspicion of drinking and driving. A DWI charge can bring serious consequences that can limit your ability to drive, work and obtain a loan. It is critical that you understand all of the options available to you if you are pulled over, changed and/or convicted of a DWI.

Many law enforcement officers use roadside breath tests to determine whether you are driving while over the legal blood alcohol content level of 0.08. The issue with these breath test machines is that they often yield inaccurate and inflated results. This could result in a wrongful DWI charge and conviction.

Blood alcohol test vs. breath test

Rather than obtain a BAC level directly from a blood sample, a breath test measures the amount of ethanol alcohol present in an exhaled breath sample. Yet, when researchers at the State University of New York at Potsdam compared blood test results with breath test readings, they noticed a variance of more than 15% in BAC levels. They also found that one out of every four people tested with a breath test device had inaccurate results.

Factors that may lead to reading errors

Breath tests can also pick up other substances that have similar methyl structures, which add to this discrepancy. Other factors that can alter breath test readings include the following:

  • Residual drinks, food, vomit or blood found in the mouth
  • Cigarette smoke, pollution or dirt in the air
  • Fumes from gasoline, cleaners or paint
  • Relative humidity and temperature of the air
  • Electrical interference from officer radios or cellphones

Not only do breath machines require regular calibration and maintenance, the officer using the machine must know how to do so properly.