ACCURACY OF BREATH TESTING IN DUI CASES: FACTORS THAT CAN INFLUENCE BREATH ALCOHOL CONTENT
The government, including the prosecutors and police will have you think that the breath testing instruments they use to determine a driver’s breath alcohol content (“BrAC”) is highly accurate and virtually fail-proof. They will usually deny that there are numerous factors that could influence a breath test reading, and there are common ways that a test result could show a significantly higher reading or lower reading than the true BrAC.
Breath Temperature Can Affect Breath Test Results
For example, if a person hyperventilates for about 20 seconds prior to taking the test, a study has shown that this causes the breath temperature to drop and this drop in temperature can result in lower the breath alcohol content by about 10.6 percent. If the DUI suspect does the opposite—hypoventilates (holds his or her breath)—and does so with his or her mouth closed, this can cause the breath temperature to rise, resulting in an increase of the breath alcohol content by about 7.3 percent. (This is partly due to the time breath is in contact with the mucous membranes in the respiratory tract and the amount of alcohol desorbed into the airways.) Therefore, the way someone breathes can significantly change the breath test results, causing a falsely high or low reading.
Dentures and bridges in the mouth could have an effect on a person’s breath test result as well. Alcohol can be retained in these objects and trapped, despite an officer conducting a 15 minute waiting period of the driver prior to conducting the breath test, as required under Title 17. One study showed that if 30 minutes is allowed prior to conducting the breath test, any trapped alcohol will have disappeared.
Medical Conditions Can Affect Breath Test Results
Diabetes and Gastroesophageal Refleux Disease (GERD) are two known medical disorders that can play a role in creating falsely high readings in breath tests. Gerd can cause alcohol in the stomach to come up during reflux, contaminating the mouth with mouth alcohol.
If you would like to know more about what factors and medical disorders can affect a DUI breath test, call attorney Ann Gottesman for more information.