The race for the roadside

With blood tests mired in a cloud of ambiguity, researchers in both the private and public sector have begun developing viable alternatives.

Among these new, and largely nascent technologies, saliva tests may hold the most immediate promise. Oral swabs are less invasive than either blood or urine samples, and therefore have the potential to provide law enforcement with a breathalyzer-like roadside alternative.

Early saliva-based methods were plagued by sensitivity issues, often resulting in false negatives, but recent years have seen an increase in deployment across the globe.

Police in Victoria, Australia launched an oral drug screening program in 2004, and have since seen encouraging results. According to the Australian Drug Foundation, these tests can be completed in just three to five minutes, and are capable of detecting cannabis "for at least several hours" after ingestion. Similar programs have been launched in Spain and Belgium, where in 2010, saliva tests permanently replaced blood-based police diagnostics.

Adoption hasn’t been nearly as rapid in the US, though that may soon change. In March, Dr. Marilyn Huestis of the National Institute on Drug Abuse (NIDA) told the Associated Press that government researchers had begun final trials on a saliva test capable of detecting recent marijuana use, and that the test would soon be ready for use in police cars.

Researchers in the private sector, meanwhile, have begun developing more forward-looking drug testing mechanisms. The UK-based startup Intelligent Fingerprinting is currently developing a fingerprint scanner capable of detecting THC in the sweat excreted from a subject’s fingertips.

The product itself is still undergoing tests and its detection window remains uncertain, but Dr. Paul Yates, Business Development Manager at Intelligent Fingerprinting, says his company expects the device to pick up on any THC ingested within a one- to two-day period.

Viable alternatives may be years away

It's a futuristic vision that may border on the draconian (Yates notes that the fingerprints could be easily linked to police databases), but it's not likely to have an impact in the US anytime soon. In an interview with The Verge, Yates said the fingerprint scanner won't be ready for market until the end of 2013, and although the company has signed a deal to distribute its product in the US, it would still need to receive FDA approval before being used as a law enforcement tool.

Sergeant Mark Crandall of the Washington State Patrol Drug Evaluation and Classification Program says he expects private sector innovation to drive the creation of new testing products, though he doesn’t foresee any major changes in the near future, noting that any technology would still need to meet federal and state scientific standards before being used in the field.

"I believe something will be invented," Crandall says, "but even once it’s invented, it would probably take years to bring it to market and then even more time to get it accepted by the court systems."