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Breathalyzer Accuracy

Pittsburgh DUI Defense Attorney

Breathalyzer Accuracy

Law enforcement and prosecutors continue to insist that breath-testing technology is accurate and reliable. That it's nearly foolproof. In fact, nothing could be further from the truth. Pittsburgh criminal defense lawyer, Blaine Jones, is devoted to keeping up with the latest technology, case law and other developments. Challenging the results of breathalyzer testing is an avenue often pursued by experienced defense attorneys. And it leads to a reduction or dismissal of the charges in a significant number of cases. Breathalyzer is actually the name of a series of breath-testing machines originally manufactured by Smith and Wesson. But the term has fallen into general use for all such machines. The National Highway Traffic Safety Administration maintains a list of approved devices for evidentiary use and preliminary screening.

BAC Breath Test Defense

The basic technology of a breath-test machine purports to break the breath down into an electrical current that can be read by a computer processor. The devices do not directly measure blood-alcohol level, which requires a blood test. Common issues include:

  • Calibration: The machines are very sensitive and often give inaccurate readings when not carefully calibrated.
  • Maintenance: The machines must be properly maintained and frequently serviced.
  • Alcohol Confusion: Some machines are not able to accurately identify ethyl alcohol (found in alcoholic beverages) or differentiate from other substances of similar molecular structure. This can create confusion and lead to false positives.
  • Interference: Some compounds may interfere with test results. The NHTSA has found that dieters and diabetics may have high levels of acetone, which is just one of the many substances that can be confused for alcohol. Any number of other products found in the environment, including the workplace, can lead to false positives.
  • Breath Volume: Machines can be confused by breath volume. In some cases conversion to blood volume is inaccurate.
  • Mouth Alcohol: Belching, acid reflux and other circumstances can result in a higher concentration of mouth alcohol, which can lead to higher reading. Dentures and periodontal disease can also create a higher reading due to excess mouth alcohol.
  • Absorption Rate: BAC is different in different parts of the body during the absorption process, which can last up to 2.5 hours after last consumption. This discrepancy is most apparent in blood testing since arterial blood-alcohol levels will generally be higher than that found in venous blood.
  • Time Frame: Elapsed time makes a difference and can result in a BAC level that is higher or lower than at the time of arrest. Other cases, particularly in alleged hit-and-run cases or cases in which a defendant spends time outside police presence, additional alcohol consumption may negatively impact results.

If you've been charged with driving under the influence, call Pittsburgh DUI lawyer, Blaine Jones, for a confidential consultation.

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