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What Can Skew the Results of Blood and Breath DUI Tests?

Posted on in Traffic Offenses

What Can Skew the Results of Blood and Breath DUI Tests?Though not the only form of evidence in a case of driving under the influence, the results from a chemical sobriety test can strongly support the claim that you were legally intoxicated at the time of your arrest. Unlike observations of your behavior, courts view the blood or breath test results as objective evidence because they measure your blood alcohol concentration and detect illegal substances in your body that may have impaired you. However, testing above the BAC limit does not always mean that you were intoxicated. Your DUI defense attorney will look into possible reasons why the test results may be inaccurate.

Breath Tests

During a traffic stop, a police officer who suspects that you are intoxicated may ask you to provide a breath sample using a portable device, such as a Breathalyzer. Breath tests are quicker and easier than blood tests but are also more prone to error:

  • Residue from substances such a mouthwash and breath fresheners may have trace amounts of alcohol in them that skew the test results.
  • The presence of nearby chemicals such as paint or adhesives can cause false results.
  • The test uses hardware that must be regularly calibrated to ensure accuracy and software that may be vulnerable to glitches.
  • The officer should conduct the breath test multiple to see that the results are consistent.

Blood Test

A police officer is more likely to take a blood sample at the police station or a hospital if you are being treated for injuries. While a blood test is considered the more accurate chemical sobriety test, there is still a possibility of inaccuracies:

  • The blood sample may be tainted if the person drawing the blood used a chemical to clean the skin before inserting the needle.
  • Leaving the blood sample unrefrigerated or exposing it to extreme heat can cause natural substances in the blood to ferment and give higher alcohol readings.
  • The police department or testing lab may have a reputation for mislabeling samples or not maintaining their machines.

Contact a Crystal Lake, Illinois, Criminal Defense Attorney

You can refuse a chemical sobriety test during a DUI stop, but doing so after you are arrested will result in an automatic suspension of your driver’s license for 12 months if this is your first DUI arrest. The suspension is a civil penalty that is independent of the outcome of your criminal case. A McHenry County DUI defense lawyer at Botto Gilbert Lancaster, PC, can help you beat your DUI charge and reinstate your driving privileges. To schedule a free consultation, call 815-338-3838.



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