Common Field Test for Marijuana is Unreliable, Critics Say

A 75-year old pot assay is due for an update.

We’ve all seen it on cop shows: The little plastic bag, the officer breaking the seal on a small pipette and inserting a bit of marijuana, then a firm shake, and voila, the liquid in the test satchel turns purple: Guilty.

Here’s an interesting twist they don’t tell you about: The so-called Duquenois-Levine test—the dominant method for field-testing marijuana since 1930—is considered by many to be wildly inaccurate, and frequently doesn’t hold up in court. One U.S. Superior Court judge referred to the test as “pseudo-scientific.”

The test itself works fine. The problem is that, in addition to identifying marijuana or hashish, the Duquenois-Levine, or D-L, frequently reads positive for tea, nutmeg, sage, and dozens of other chemicals—including resorcinols, a family of over-the-counter medicines, which, according to John Kelly at AlterNet, includes Sucrets throat lozenges. This does matter, because in New York, Washington, D.C., and elsewhere, inner-city minority kids are getting busted for pot in record numbers. Lacking a reliable test protocol, marijuana is whatever the officer says it is. In a classic case that continues to bedevil the testing industry, a middle-aged woman was busted for marijuana while bird watching. A “leafy substance” turned purple on the Duquenois-Levine (D-L) test, and the woman was arrested. The material turned out to be sage, sweetgrass, and lavender, and the woman was engaging in a Native American purifying ritual using a smudge, a concept with which the arresting officers were unfamiliar.

So, when push comes to shove, a positive D-L rarely establishes the presence of marijuana beyond a reasonable doubt, without further confirmatory testing. For at least 20 years now, a visual inspection and a NarcoPouch, as the D-L field test is called, were enough to bring on the felony charges. State courts have squabbled over the matter, but state legislatures have been reluctant to intervene, in large part because sending samples to a lab for confirmatory testing is prohibitively expensive, particularly when the busts are small. The D-L test saves money.

According to the official drug policy of the United Nations, a positive marijuana ID requires gas chromatography/mass spectrometry analysis. And even this far more sophisticated test has angered courts in Washington and Colorado, the UK Guardian reports, “because the DEA doesn’t have standard lab protocols to govern its use.” In part, the judges are furious because plea-bargaining depends upon valid drug possession evidence. So, the officers themselves, when it comes to testifying in court, become de facto expert witnesses, able to identify illegal drugs on sight. Ah, those were the days. But now, cannabis-based products come in a bewildering variety of sizes, shapes, colors, smells, and chemical compositions.

But c’mon, if it looks like bud and it smells like bud… except that the research shows there are 120 terpenoid-type compounds involved in the odor of marijuana. No two varieties smell exactly alike. There is no characteristic marijuana smell—there are hundreds of characteristic marijuana smells. Nonetheless, in 2009 the National Academy of Sciences called the testing of controlled substances “a mature forensic science discipline,” according to AlterNet.

In a 2008 article for the Texas Tech Law Review, Frederic Whitehurst, Executive Director for the Forensic Justice Project and formerly with the FBI, concluded: “We are arresting vast numbers of citizens for possession of a substance that we cannot identify by utilizing the forensic protocol that is presently in use in most crime labs in the United States.” In another section of the article, Whitehurst asks: “Why is this protocol still being utilized to decide whether human beings should be confined to cages and at times, to death chambers?” And as Stewart J. Lawrence and John Kelly write in the Guardian, “using manifestly flawed drug identification tests to charge defendants, or pressure them to plead guilty, is hard to square with a defendant’s right to due process.”

Photo Credit: http://www.howardcountydui.com/ 

There’s No Agreement on DUIC: Driving Under the Influence of Cannabis

The ACLU squares off against law enforcement over how to measure marijuana impairment.

What’s your blood cannabis content? You don’t know, and neither does anybody else, without a fair bit of effort. There’s no device to blow into, no quick chemical field test. You’re impaired by marijuana if the officer says you’re impaired by marijuana, and in most states he or she will decide that matter by using a series of sobriety checks not dissimilar to the well-known alcohol exercises: standing on one foot, walking a line, having your eyeballs and blood pressure checked—and my personal favorite, a test of how well you can guess when 30 seconds is up. Time passes more slowly when you’re about to be arrested for drugs, I’m guessing, since it takes a little while for your life to pass before your eyes. Even the National Highway Traffic Safety Administration admits that it is “difficult to establish a relationship between a person's THC blood or plasma concentration and performance impairing effects. Concentrations of parent drug and metabolite are very dependent on pattern of use as well as dose."

The point is, observable indications of impairment, as they’re called, are really all that law enforcement currently has as a tool for policing the use by drivers of American’s second most popular drug. At one extreme end of the spectrum are the pot enthusiasts who argue that no amount of marijuana significantly impairs you behind the wheel. At the other end of the spectrum stand the zero-tolerance advocates: No amount of marijuana is safe, if you’re planning to get behind the wheel within the next several hours—or at any time during the rest of your life, as some anti-drug advocates seem to be saying.

And somewhere in between, according to the American Civil Liberties Union (ACLU) of Washington State, lies a possible compromise for gauging marijuana impairment. “Adding a science-based threshold for likely impairment to the mix and providing educational information that allows people to estimate their personal level of intoxication can be effective strategies for preventing impaired driving in the first place and improving public safety,” the  ACLU asserts.

The ACLU favors the so-called Pennsylvania Model, which sets that state’s legal limit for cannabis in whole blood at 5 nanograms per milliliter (ng/mL). Why 5, and not some other number? Because a legal cut-off of 5 ng/mL is also what the National Organizaton for the Reform of Marijuana Laws (NORML) recommends, based in turn on an analysis of scientific studies of marijuana’s effect on driving skills. Specifically, NORML recommends a limit in the range of 3.5-5.0 ng/mL, which the group says will “clearly separate unimpaired drivers with residual THC concentrations of 0-2 ng/mL from drivers who consumed cannabis within the last hour or so.” Levels under that range tend to indicate that the driver smoked at least 1 to 3 hours ago. Anyone testing over that range, says NORML is “likely to be impaired.”

But it’s not quite that simple, of course. First, you have to rule out a whole roster of cannabis metabolites that stay in the system for days or weeks, but have no impact on driving skills. And the metabolism of cannabinoid by-products varies so widely from person to person (this is just beginning to be understood scientifically), that the results of testing are not foolproof. The iron law of metabolic diversity makes that claim unlikely. Moreover, there is currently no reliable way of testing blood in the field for THC concentrations. But there will be. Introducing the Vantix Biosensor, a device that looks, ironically, like a portable vaporizer for marijuana. Open your mouth, please, as the officer politely swabs the inside of your cheek with a plastic wand, and inserts the wand in the handheld machine. Sensors on a microchip react with telltale antibodies, and you test positive for cocaine, or marijuana, or, soon, synthetic marijuana. Or perhaps it will be some other company’s device. But rest assured it is being looked upon as a growth market.

And then there is, as the ACLU points out, the wrong way to go about it: zero tolerance. At least 11 states have now set the requisite cut-off level for illegal drugs at zero. That may raise a cheer in certain quarters of the anti-drug movement, but it is a decision “based not in science but on convenience,” says the ACLU. It establishes a crime wholly “divorced from impairment” behind the wheel. Put simply, zero tolerance “does not differentiate between a dangerously incapacitated driver and an individual who may have smoked the past Monday but was pulled over as a sober ‘designated driver’ on Saturday night.” Furthermore, “even a statute excluding cannabis metabolites but criminalizing trace amounts of THC” could result in the arrest of drivers several days after they last smoked pot. It’s pretty simple, really. “If science dictates that the presence of a trace amount of cannabis or a cannabis metabolite in an individual’s blood has NO ‘influence’ on his capacity to drive, it should not constitute per se evidence of ‘driving under the influence.’” But toxicologist Marilyn Huestis, at the National Institute on Drug Abuse, disagrees. She believes that there is no safe level of marijuana consumption, where driving is concerned. Paul Armentano, deputy director for NORML, scoffs at that, telling the Los Angeles Times that individual states “are not setting a standard based on impairment, but one similar to saying that if you have one sip of alcohol you are too drunk to drive for the next week.”

 One abiding problem is that for car accidents, it’s not necessarily a pure play. Alcohol mixed with one or more additional drugs is common, and if it’s difficult to set limits for alcohol and marijuana alone, imagine the permutations involved in creating legal limits for a combination of both. A 2007 survey of experimental studies, published in Addiction by a group of researchers in six countries, concluded that a rule of thumb police might want to consider is based on the finding that “a THC concentration in the serum of 7–10 ng/ml is correlated with an impairment comparable to that caused by a blood alcohol concentration (BAC) of 0.05%. Thus, a suitable numerical limit for THC in serum may fall in that range.” Considering that we allow drivers to exhibit blood alcohol limits as high as 0.08, NORML’s 5 ng/mL limit looks downright conservative.

There’s no simple solution. Maybe that’s because cannabis is not a simple drug. We’re still teasing apart its effects, and nailing down the particulars of driving under the influence of cannabis is one of them. As Jeffrey P. Michael of the National Highway Traffic Safety Adminstration refreshingly disclosed to the Los Angeles Times, “We don’t know what level of marijuana impairs a driver.” But they are trying to find out. A federal study in Virginia intends to round up more than 7,000 blood samples by showing up at the scene of car accidents and asking drivers to provide random, anonymous  samples to compare with control samples.

Other studies of a similar nature are underway. Driving under the influence of drugs could become as common a criminal charge as classic DUIs and DWIs.

Photo credit: http://www.janisian.com/

Pot Advocates Overreach Themselves

L.A. set to close most marijuana dispensaries.

Medical marijuana advocates in Los Angeles appear to have overreached themselves, angering the City Council by establishing more than a thousand medical marijuana dispensaries in commercial and residential neighborhoods around the city.

According to a report by Jennifer Steinhauer in the New York Times, a board member for the neighborhood council in Studio City called the 13 dispensaries in her 3.5 square miles-neighborhood “unbelievable.”

The City Council struck back hard on Tuesday, passing a city ordinance that would “shutter the majority of the nearly 1,000 medical marijuana dispensaries in Los Angeles and make the use of marijuana in the remaining outlets illegal,” according to the New York Times article. Claiming that Los Angeles now had more marijuana dispensaries than Starbucks outlets, Councilman Ed Reyes, chairman of the planning and land-use management committee, called the situation “out of control.”

Two years ago, Los Angeles imposed a moratorium on the establishment of new dispensaries, pending further study. But medical marijuana advocates flouted the temporary ban with impunity. According to the article, “The measure, which passed on a 9-to-3 vote, imposes strict rules on the location of the dispensaries — essentially moving them to more densely industrial zones — and restricts their hours. The ordinance, which city officials acknowledge would be difficult to enforce, will limit the number of dispensaries to 70….”

According to the Los Angeles Times :  “In a 9-3 vote, the Los Angeles City Council today gave its final approval to an ordinance that will shut down hundreds of medical marijuana dispensaries and impose strict rules on the location and operation of the dispensaries that are allowed. The ordinance, which the council first began discussing more than 4 1/2 years ago, will cap the number of dispensaries at 70 but make an exception to allow all those that registered with the city in 2007 and have remained open. City officials believe that number is around 150.”

Photo Credit: http://seattletimes.nwsource.com/html/nationworld/2010085782_lapot18.html

Medical Marijuana Can Get You Fired

California Supreme Court sides with Feds.

The California Supreme Court ruled on Thursday that employers have the right to fire workers who test positive for marijuana—even if the pot is being used in line with California’s medical marijuana statutes.

In a 5-2 decision, the Court said that a Sacramento company had the right to fire an employee who tested positive for marijuana on a routine drug test, even though the employee had a letter from his physician recommending the use of marijuana for chronic pain due to a back injury suffered in the Air Force.

Justice Kathryn Werdegar, writing for the majority, made clear the legal tangle created when California voters passed an initiative in 1996 allowing the use of marijuana for medical purposes: “No state law could completely legalize marijuana for medical purposes because the drug remains illegal under federal law, even for medical users.”

Last year, a San Francisco federal court ruled that a woman with a brain tumor did not have a fundamental right of access to marijuana for medical treatment. In addition, the Drug Enforcement Administration (DEA) shut down several medical marijuana dispensing centers and made several arrests for felony distribution. Yesterday’s ruling bolsters the contention that federal law trumps state statutes.

The Pacific Legal Foundation filed a brief in support of the employer’s position in the case. “What are they supposed to do?” said Pacific Legal Foundation’s Deborah LaFetra. “Employers are held liable all the time when drunk or stoned employees cause trouble, either in the workplace or driving home.”

A spokesperson for Americans for Safe Access, a medical marijuana advocacy group based in Oakland, said they would go back to the California State legislature seeking to protect workers who use pot for medical reasons. According to the group, at least 200,000 workers in California may now be using marijuana under a doctor’s recommendation. “We remain confident that there will be a day when medical marijuana patients are not discriminated against in the workplace,” the spokesperson said.

photo credit: In These Times
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