Challenging DWI Breath Test Inaccuracy

Posted By Guerra & Farah, PLLC || 10-May-2012

Are breath tests sometimes inaccurate? Absolutely, and an experienced Texas DWI lawyer may be able to defend against charges based on a flawed breathalyzer test.

Texas has over 40 Technical Supervisor Areas that oversee breath alcohol testing to ensure test regulations are enforced. The supervisor is responsible for seeing that the testers, which may be police officers or other personnel, properly administer breath tests. According to the Texas Breath Alcohol Testing Program, testers use the Intoxilyzer 5000.

However, inaccuracies are common. An article entitled Variables Affecting the Accuracy and Precision of Breath Alcohol Instruments Including the Intoxilyzer 5000 by Stefan Rose, M.D. and Kenneth G. Furton, Ph.D. explains that the Intoxilyzer 5000 is prone to false positives because it can:

  • Respond to other chemicals besides ethanol
  • Read based on falsely elevated breath levels such as hyperventilation
  • Read differently based on abnormal body temperature (fever)
  • Vary significantly depending on whether the person is still absorbing or is eliminating alcohol
  • Read based on disease, trauma and other drugs that affect breathing rates which can cause a false positive

An incorrectly calibrated breathalyzer or one not properly maintained also gives flawed test results. Never assume there is nothing you can do about a DWI arrest. Many Texas DWI attorneys challenge the validity of the breath test and help clients fight against conviction.