Inaccuracies of Breath Testing

Breathalyzer is the brand name for the gadget invented by Robert Frank Borkenstein in 1958, used for estimating blood alcohol content (BAC) from a breath sample.  Now almost sixty years later, the trademarked “Breathalyzer” has become a much more generic term and evolved into a very tech savvy instrument.  Portable, light in weight, and easy to administer, law enforcement can use the apparatus to perform a breath test, assess BAC, and assist in establishing probable cause in a driving under the influence (DUI) arrest.  However, the accuracy of breath test results is being questioned.

In California and all of the other forty-nine states, it is unlawful to operate a motor vehicle with a BAC of .

08% or higher.  In some circumstances, such as with a commercial driver license or for those under the age of 21, the BAC limit is even lower or zero tolerance.  With probable cause to believe one is under the influence, law enforcement can perform breath testing in the field as a preliminary measure.  If a driver provides a breath sample and is found to be at the .08% threshold or higher, a driver is presumed to be legally “drunk” and may be charged with DUI.

BAC, also referred to as blood alcohol concentration, can be measured with a number of methods.

Breath testing, administered with a handheld Breathalyzer device, has come to be most commonly used, especially during field sobriety tests.   Using a complex formula programmed into the device, a breath test can provide immediate results that is supposed to determine the percent of one’s blood, by volume, which is alcohol.

Despite improved technology, a breath analyzer device can be affected by various outside factors, resulting in questionable accuracy.  Any one factor may produce fluctuated readings and cause breath results to appear skewed.  The reliability of testing can depend upon, but not limited to the following:

• The maintenance, calibration, and good repair of the testing software
• Pattern of breathing, whether hyperventilating, breathing hard or holding breath
• Testing administration and administer following precise procedure training
• Presence of mouth alcohol, which can derive from something as simple as burping or the use of mouthwash
• Interfering biological circumstances of the tested individual, such as their diet or if they smoke
• Interfering medical conditions of the tested individual, such as diabetes or acid reflux (The National Highway Traffic Safety Administration has reported that dieters and diabetics may have certain levels that are higher than those in others.)

While the accuracy of breath test results is being challenged and addressed across the nation, science and technology are evolving.  For the time being, for individuals charged with DUI, breath tests results are evidence, and can be admissible in court.