SAN DIEGO DUI DEFENSE: BREATHALYZER TESTS ARE AN INACCURATE MEASUREMENT OF BLOOD ALCOHOL CONTENT
A group of judges in New Hampshire was served several alcoholic drinks as part of an experiment that was intended to demonstrate the effectiveness of the Breathalyzer. One judge was given so many drinks that he became visibly intoxicated. When the judge blew into the Breathalyzer, the machine registered a score of 0.0. After a few more tries, the Breathalyzer gave the same result. Following the demonstration, at least one police jurisdiction in the state ceased using the Breathalyzer in favor of blood tests. (See Margaret Graham Tebo, New Test for DUI Defense, ABA Journal (Feb. 2005).)
The Breathalyzer is by far a less accurate test than a blood test. A blood test actually measures blood alcohol concentration (BAC). But a Breathalyzer merely estimates it. It measures "breath" alcohol concentration, and requires a difficult mathmatical conversion to correlate it to a "blood" alcohol concentration.
What the Breathalyzer attempts to measure is the presence of chemicals found in alcohol. But the machine often measures chemicals with molecular structures similar to those found in alcohol. There are, in fact, there are numerous chemical compounds that can fool a Breathalyzer machine.
According to Dr. David Hanson, Over 100 compounds can be found in the human breath at any one time, and 70 to 80 percent of them contain [a] methyl group structure and will be incorrectly detected as ethyl alcohol. (See David Hanson, Ph.D., Breath Analyzer Accuracy, at http://www2.potsdam.edu/hansondj/DrivingIssues/1055505643.html.) As a result, false positives can occur for a plethora of reasons.
Body chemistry is one factor that can lead to false positives. People with diabetes, acid reflux disease, or some cancers can fail Breathalyzer tests even if their bloodstreams are perfectly free of alcohol. Diabetics, for example, have extraordinarily high levels of acetone, a substance that some breath machines mistake for ethyl alcohol.
Police recognize that regurgitation can render unreliable the results of a Breathalyzer. Thus, most departments require that the arresting officer observe the subject of a breath test for a period of time prior to administerting the test. In California, police should watch the suspect for at least fifteen minutes to make sure he or she did not burp, hiccup or regurgitate prior to applying the test. Regurgitation includes any instance of fluids or gases that rise through the esophagus.
In 2004, the Illinois Supreme Court ruled inadmissible the results of a breath test where the defendant presented evidence of gastroesophageal reflux disease (GERD). In People v. Bonutti, 817 N.E.2d 489 (Ill. 2004), the defendant had blown a BAC of 0.174 after being stopped and showing outward signs of intoxication. Defendants motion to suppress the Breathalyzer evidence was granted because the court found that the results could have been compromised by a silent, unobservable episode of reflux.
Two years ago, when I attended the Intox 8000 Certification seminar in New Orleans (the San Diego Police Department had just implemented the machine), I was able to get a Fort Lauderdale judge who was acting as a guinney pig for us to blow a .20 breath alcohol level using the Intox 8000 machine. His true blood alcohol level at the time was .02 (he had one drink in him). I got the machine to measure a breath alcohol concentration of ten times the actual true blood alcohol level. How? I just manipulated the machine and the judge's breathing techniques.
If you think I can do this, imagine the flawed results an inexperienced cop might use against you?
Non-alcoholic substances that people commonly ingest can register on the Breathalyzer. Smokers are often told to wait after consuming a cigarette because chemicals in the smoke can trick the machine. Some non-intoxicating, over-the-counter medications can do the same thing.
Even various types of breads can account for BAC levels up to 0.05. I have actually had my expert chew Wonder Bread in front of a jury and blow a .05 breath alcohol level using a preliminary alcohol screening device. The yeast in the bread mixes with the saliva, and you get a breath alcohol reading after just a few minutes.
The Breathalyzer is also susceptible to error caused by environmental factors. If a driver has recently pumped gasoline, or pained a house, the alcohol in the fuel or paint can remain on the hands or clothes and can waft into the machine. Compounds that contain the methyl group structure appear in everyday chemicals, such as those found in paints, paint removers, and cleaners. Even electrical interference from cell phones and police radios can disturb the machine.
Women tend to be at a higher risk of registering a false positive than men. Some breath analysis machines presume a specified hematocrit, which is the percentage of whole blood that is composed of red blood cells. Men naturally have higher hematocrit values than women, but the machines do not adjust according to the sex of the subject. A person with lower hematocrit might have an artificially high BAC reading. Thus, women as a class are in jeopardy of this kind of error. (Hematocrit values can also fall due to blood loss; so, a person tested after being in an accident can register a false positive, adding insult to injury.)
Portable Breathalyzers, which are utilized at traffic stops, are even less reliable than their stationary counterparts. In most jurisdictions, the results from a portable Breathalyzer machine merely provide probable cause to arrest drivers. These machines are susceptible to inaccuracy for reasons as simple as the administering officers improper calibration or carbon monoxide emissions from passing cars.
Traditionally, defending a DUI case consisted of attacking the arresting officers probable cause, the officers training in recognizing intoxication, and the polices chain of custody for physical evidence. But as the state relies increasingly on technology to prove its cases, defense attorneys must stay a step ahead in their understanding of the equipment and its shortcomings.
Likewise, a criminal defendant should not concede the accuracy of a Breathalyzer but should hire an experienced attorney who has the time and energy to ensure that dubious test results do not become evidence at trial.
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