Category Archives: Duiblog

Urinalysis: Unreliable for Blood-Alcohol

In many states, a suspect’s blood-alcohol concentration can be determined with urinalysis. This is consistently the least accurate of the three available methods of analysis. The reasons for this are basically two.First, the test is completely dependent on the subject voiding his bladder and then waiting 20 minutes for fresh urine to be secreted into the bladder for a more representative sample. And it is virtually impossible for an individual to completely void his bladder: There will usually be about 10cc of old urine left. This urine will combine with approximately 20cc of fresh urine produced during the wait, resulting in a sample that is one-third old urine — a sample that will contain alcohol from many hours before the subject was driving.

Second, urine often contains a yeast called Candida albicans. This organism has an interesting characteristic: it manufactures alcohol in the urine (caused by the interaction with glucose). This "immaculate conception" of alcohol in the bladder has been confirmed by numerous scientific studies. See, for example, "Bladder Beer — A New Clinical Observation", 95 Transactions of the American Clinical Climatological Association 34. To make things more interesting, Candida albicans is also unaffected by preservatives added by the police to urine specimens. In other words, alcohol will continue to be produced inside the evidence vial for days until it is finally analyzed at the crime lab.

How Not to Beat the Breathalyzer

Item from the Red Deer (Alberta, Canada) Advocate:

MAN EATS UNDERWEAR TO BEAT BREATHALYZER

STETTLER — An 18-year old Stettler man tried to eat his underwear in the hope that the cotton fabric would absorb alcohol before he took a breathalyzer test, provincial court heard this week.

David Zurfluh was subsequently acquitted of a charge of impaired driving because he blew .08, the legal limit. But the testimony broke up people in Judge David MacNaughton’s provincial court here Thursday afternoon.

Mr. Zurfluh was collared by RCMP Const. Bill Robinson after he ran from his vehicle, which had been seen weaving down the highway. While sitting in the back of the patrol car, Mr. Zurfluh tried to eat his shorts, Const. Robinson told the court.

Mr. Zurfluh said he ripped the crotch out of his shorts, stuffed the fabric in his mouth and then spit it out. A class of law students from William E. Hay Composite High, in court as observers, was removed by the teacher when testimony enlivened the proceedings.

The Grade 11 and 12 students had difficulty maintaining composure. "People were leaving the courtroom with tears in their eyes, trying not to laugh," said RCMP Const. Peter McFarlane.

“Slurred Speech”: Evidence of DUI?

As with the odor of alcohol on the breath, few police reports will fail to include an observation by the arresting officer that the arrestee exhibited “slurred speech”. (See my earlier post, “Alcohol on the Breath: Evidence of DUI?”). The officer fully expects to hear slurred speech in a person he suspects is intoxicated, particularly after smelling alcohol on the breath, and we tend to “hear” what we expect to hear. And hearing it supplies the officer with corroboration of his suspicions.

Even assuming the honesty of the officer that the defendant’s speech was slurred, there is little evidence that this is symptomatic of intoxication. Impairment of speech is, for example, a common — and sober — reaction to the stress, fear and nervousness that a police investigation would be expected to engender; fatigue is another well-known cause. However, consider the following excerpt from Discover magazine:

“Bartenders, police officers and hospital workers routinely identify drunks by their slurred speech. Several investigative groups judged the captain of the Exxon Valdez oil tanker to be intoxicated based solely on the sound of his voice in his radio transmissions. But a team led by Harry Holien, a phonetician at the University of Florida, has found that even self-proclaimed experts are pretty bad at estimating people’s alcohol levels by the way they talk.”

Hollien asked clinicians who treat chemical dependency, along with a group of everyday people, to listen to recordings made by volunteers when they were sober, then mildly intoxicated, legally impaired, and finally, completely smashed. Listeners consistently overestimated the drunkeness of mildly intoxicated subjects. Conversely, they underestimated the alcohol levels of those who were most inebriated. Professionals were little better at perceiving the truth than the ordinary Joes…. “

He thinks his research could encourage police to be more wary of making snap judgments: Mild drinkers might come under needless suspicion…” Saunders, “News of Science, Medicine and Technology: Straight Talk”, 21(1) Discover (Oct. 2000).

Asthma Inhalers Cause High Breathalyzer Results

If you use asthma inhalers and are ever arrested for DUI, you should perhaps think twice about taking a breath test. Most inhalers operate primarily by injecting a mist containing a substantial quantity of alcohol into the lungs. As an example, one of the most commonly used inhalers, Primatene Mist, contains 34 percent alcohol. This alcohol does not pass into the blood stream, but remains in the alveolar lining of the lungs — from where it will be exhaled into the breath machine.

The problem is that "breathalyzers" are designed to assume that the breath sample contains alcohol which has been swallowed and then metabolized by the body before being diffused into the lungs. As I mentioned in an earlier post ("Breathalyzers — and Why They Don’t Work"), they are further designed to assume that there are 2100 units of alcohol in the blood for every unit measured on the breath. So the breathalyzer’s computer mistakenly multiplies the alcohol measured from the asthma inhaler 2100 times. In other words, a very tiny amount of alcohol in the lungs from the inhaler mist can have a very large effect on the machine’s reading.

Just to make things worse, scientists have found that some asthma inhalers can cause high readings on breath machines due, apparently, to the propellent gasses used in the aerosols, in particular, chlorofluorocarbons. See "Using Asthma Inhalers Can Give False Positive Results in Breath Tests", 324 British Medical Journal 756 (March, 2002). As I mentioned in another earlier post ("Why Breathalyzers Don’t Measure Alcohol"), one of the many design defects in breath machines is that they are non-specific — that is, they will falsely report thousands of different chemical compounds as being alcohol.

Driving Under the Influence of….Paint?

In my post "Why Breathalyzers Don’t Measure Alcohol", I mentioned one of the many reliability problems breath machines have: they will falsely report any of thousands of chemical compounds as "alcohol". Scientific studies have clearly proven this defect, referred to as "non-specificity".

In "Driving Under the Influence of…Gasoline?", I gave a practical example of one such compound. Is gasoline the only chemical product that has been proven to falsely register as alcohol on these machines? Far from it. See, for example, "The Response of the Intoxilyzer 4011AS to a Number of Possible Interfering Substances", 35(4) Journal of Forensic Sciences 797, where researchers found numerous common substances which were falsely reported by breathalyzers as alcohol — including methyl ethyl ketone, which is used in lacquers, paint removers, cements, adhesives, celluloid and cleaning fluids. Another compound, toluene, also caused false high readings and is commonly used in paints, lacquers, varnishes and glues. A third chemical is isopropanol, commonly known as rubbing alcohol. Fumes from these chemicals can be inhaled or absorbed through the skin.

In an interesting scientific study, researchers performed tests on a professional painter who was exposed to lacquer fumes under controlled conditions. In the first test, he sprayed paint in a room for 20 minutes, wearing a protective mask; his blood and breath were then tested. Although the blood test showed no presence of alcohol, a breath machine (Intoxilyzer 5000) indicated a reading of .075% blood-alcohol concentration –very close to the legal limit of .08%. "Lacquer Fumes and the Intoxilyzer", 12 Journal of Analytical Toxicology 168.

Yet another scientific study discovered that diethyl ether, found in some plastics and automotive products, can be inhaled and detected by breathalyzers as "alcohol". "Diethyl Ether Interference with Infrared Breath Analysis", 16 Journal of Analytical Toxicology (1992). The researchers concluded that "the possibility of interference with an alcohol reading by ether or by other substances may therefore render prosecution more difficult if not impossible."