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Medical Condition That Can Affect A DWI Breath Test

A 64-year-old woman in Canada was arrested for refusing to submit to a breath test after a police officer stopped her for suspicion of driving while intoxicated. Police suspended the woman’s driver’s license for 90 days and impounded her vehicle. However, the woman claims that she did not refuse the test but was unable to complete it due to a chronic lung disease. The woman has a condition called chronic obstructive pulmonary disease, which restricts her breathing ability. When the woman could not sustain her breath long enough to give a sample, the officer assumed that she was purposefully not complying. Drivers suspected of DWI should inform officers of health conditions that may affect the outcome of a sobriety test.

Breath Test Accuracy

Breath and blood tests are the most common ways for police officers to determine whether a DWI suspect has a blood alcohol concentration greater than the legal limit. Officers commonly use breath tests first because they are cheaper and easier to administer. However, they are also less accurate than blood tests because:

  • Substances other than alcohol can cause false positives;

  • The technology must be calibrated and updated;

  • Human error is possible in administering the test;

  • Multiple samples must be taken to increase the likelihood of accuracy.

Health Complications

Breath tests are already an imperfect means of determining BAC, before considering how health conditions can affect the results. There are several examples:

  • People with lung diseases may be unable to provide the sustained five-second breath needed for an accurate reading;

  • People with diabetes may have acetone in their breath, which the test may mistake for alcohol;

  • Gastro-esophageal reflux disease may cause a breath test to read chemicals from the stomach instead of the lungs;

  • People’s natural body chemistry can affect the results of the test.

If a DWI suspect voices legitimate concerns about his or her ability to provide an accurate breath sample, the police officer should offer alternative means of sobriety testing instead of assuming that the suspect is being disobedient.

Breath Test Defense

An experienced DWI attorney knows that a DWI case is vulnerable if its evidence relies on breath test results. Certain health conditions can cast reasonable doubt about the accuracy of the test results. If the officer did not follow up with a blood test, the prosecution may lack chemical evidence to prove that the driver had a BAC greater than the legal limit. The Law Office of Stephens & Rueda can contest the results of a breath test in your case. To schedule a free consultation, call 214-528-5353.

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