Breathalyzers don’t test you. They test the “average” DUI suspect.
Breathalyzers cannot adjust themselves to every individual who provides a breath sample. Therefore they are calibrated to assume that all people who provide a breath sample are all the same. The breathalyzer assumes that no one has gastroesophageal reflux disease (GERD), no one is dieting, no one is hypoglycemic, and that everyone has the same core body temperature of 98.6 degrees.
This, of course, is not true. In fact, we are all different. And many people who provide breath samples after a California DUI stop do suffer from GERD, are on a diet, are hypoglycemic, and have an elevated body temperature.
And unfortunately all of these things, including an elevated temperature can cause a false reading on a breathalyzer.
In a 1989 study which was published in the Journal of Forensic Sciences test the effect of body temperature on breathalyzer results. Subjects were given a breathalyzer and a blood test after sitting in a hot bath tub. The breathalyzer readings were significantly higher than the blood tests.
In the 1990 study “The Myth of Breath Test Accuracy, What the Studies Have Really Shown,” researchers concluded that one degree centigrade change in breath temperature can cause a change in blood alcohol content reading by 6.5 percent.
Other studies have estimated the change to be as high as 9 percent. This could be the difference between a blood alcohol content reading of 0.07 percent and a 0.08 percent, which we all know is illegal to drive with.