New device claims roadside testing for marijuana within 90 seconds

(Technology Review) Later this year, Philips will introduce a handheld electronic device that uses magnetic nanoparticles to screen for five major recreational drugs.

Philips’ drug tester uses a cartridge containing magnetic nanoparticles and a handheld analyzer. Frustrated total internal reflection (FTIR) is used to detect five major recreational drugs in 90 seconds.

The device is intended for roadside use by law enforcement agencies and includes a disposable plastic cartridge and a handheld analyzer. The cartridge has two components: a sample collector for gathering saliva and a measurement chamber containing magnetic nanoparticles. The particles are coated with ligands that bind to one of five different drug groups: cocaine, heroin, cannabis, amphetamine, and methamphetamine.

The test takes less than 90 seconds and can detect drugs at concentrations measured in parts-per-billion using a single microliter of saliva.

The combination of high sensitivity, low sample volumes, miniaturization, speed, and ease of use has raised hopes for a handheld biosensor that could perform sophisticated tests with high accuracy.

I will get Paul Armentano on the program to discuss this further.  Back in January, he wrote on the subject:

Because saliva tests detect the presence of THC, not marijuana’s inactive metabolites, and have a much more narrow window of detection compared to urinalysis, advocates of the technology believe that it is far more likely than urine testing to provide evidence regarding whether someone may be under the influence of cannabis.

The article examined findings in France that saliva testing “fails to detect the recent use of cannabis over 50 percent of the time” and that “saliva testing is rarely sensitive to THC beyond one or two hours after past use, and that false positive results are not uncommon.”  However, if this is new technology, these studies may not apply.

I’m conflicted about this one.  On one hand, one of the biggest obstacles we face in legalization is the fear of stoned drivers.  If a technology exists that will accurately detect recent and possibly impairing marijuana use in drivers, that could go a long way in removing that obstacle in the minds of many.  However, on the other hand, we’re once again confusing the body’s chemical composition with a driver’s actual impairment.  No matter where you set the line – anywhere from 2ng/ml to 5mg/ml – you will have people who pass the legal threshhold but are actually quite fine to drive.  (I suppose you could make the same argument about .08 BAC in a drinking driver, too.)