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Breath test devices may not yield accurate results

Many people in Boston enjoy having a few drinks when out for dinner or a night on the town. People who choose to get behind the wheel after drinking, however, run the risk of getting pulled over by state law enforcement officers. In order to tell whether a person is driving with a blood alcohol content level that is over the legal limit of 0.08 percent, officers may use roadside breath test devices. While these machines are designed to measure the amount of ethanol that is in a person’s system, multiple studies show that device readings are not always accurate.

The Supreme Judicial Court, in response to defense arguments originating in two different Massachusetts court cases, recently ordered a hearing to review the reliability of certain breath test device models. In both cases, defendants claimed they were unjustly charged with a DUI due to faulty breathalyzer readings.

Measuring more than just ethanol

One problem with breath test devices is that they have been found to measure more than simply the amount of ethanol alcohol in a person’s breath sample. According to research performed at State University of New York at Potsdam, breath tests also pick up other compounds contained in saliva. The researchers found that blood alcohol content (“BAC”) readings can be affected by many environmental factors including:

  • Dirt and pollution in the air
  • Relative humidity of the atmosphere
  • Cigarette smoke and gasoline fumes
  • Waves from electronic devices, such as officers’ radios or cellphones

In addition to these factors, any residual food, blood or vomit left in a person’s mouth may also influence the results of the test.

Breath test devices also must be properly maintained in order to ensure accurate results. This involves calibrating them on a regular basis. All law officers who are designated to operate the devices should be well trained on how to use them, as user error can make test results inaccurate as well.

Breath tests vs. blood tests

A person’s blood alcohol content level can be measured directly through a blood test or indirectly through a breath test. When researchers compared the results of the two tests, however, the results varied significantly. In fact, in one out of every four cases, the BAC readings obtained from a breath test device measured higher than the BAC levels obtained from a blood test. The potentially devastating consequences from these errors can not be underestimated.

Protecting your rights

If you have been charged with a DUI in Massachusetts, you should seek legal assistance from a knowledgeable criminal defense attorney, who knows the law and can navigate your case into the best possible outcome. You have legal rights and you need to make sure they are protected.


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