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Questioning the accuracy of breathalyzer tests

On Behalf of | Jun 2, 2023 | DWI Defense |

Breath tests are commonly used in DWI cases to determine an individual’s blood alcohol concentration (BAC). However, these tests are not always accurate and can be subject to errors or limitations. If you’re facing a DWI charge based on a breath test result, knowing what factors can affect its accuracy can help you build on your potential defenses.

What can affect a breath test’s accuracy?

A breathalyzer works by detecting the presence of alcohol in a person’s breath. When an individual ingests alcohol, it enters the bloodstream, is carried to the lungs and evaporates into the breath. The breathalyzer calculates the amount of alcohol in the breath to estimate the corresponding BAC. Certain factors can affect the results’ accuracy, such as:

  • Residual alcohol-containing mouthwash or breath fresheners
  • Substances like paint fumes or cleaning agents in the testing environment
  • Device calibration and improper maintenance of the device
  • Breath temperature and breathing patterns
  • A person’s metabolism and other medical conditions like acid reflux or diabetes

The results of a breath test can then be used as evidence of impairment if it indicates an elevated BAC. However, it is crucial to remember that breath tests are not infallible. They serve as a preliminary measure. Enforcers often follow it with blood tests for confirmation.

Questioning the validity of the results

To address concerns about breathalyzer accuracy, defense attorneys often challenge the reliability of these tests in court. They may question the calibration records, maintenance history or the training of the law enforcement officer administering the test. In some cases, the defense can call on an expert witness to present alternative explanations or evidence that disputes the validity of the breathalyzer results.

Getting a DWI charge based on breathalyzer tests can result in fines and penalties. But while they provide law enforcement with a means to detect potential DWI offenders on the road, it has limitations and is not always accurate.