Can Drug Use Be Detected Through Your Fingertips?

By Bryan Le 04/16/18

An advanced new drug-testing method can reportedly identify cocaine use 99% of the time.

View of a fingerprint revealed by printing.
It's not just who you are, but what you've done, too.

A fingerprint has long been used to mark who you are, but could soon help law enforcement know which drugs you’ve handled—and whether you’ve used them, too.

Researchers at the United Kingdom’s University of Surrey claim to be able to detect the presence of cocaine and opiates within 30 seconds, from just a single fingerprint.

The researchers tested their method with 160 fingerprints from 16 people at a drug treatment center who had used cocaine within the past 24 hours and compared those prints with 80 "clean" prints from non-users.

The testing method was able to correctly identify 99% of cocaine users, confirmed with saliva tests, even after they washed their hands with soap and water. The method also only returned false positives 2.5% of the time.

They believe their method can be extrapolated to detect other drugs, like meth, marijuana, and even legal prescription drugs. However, some are concerned that the technology could be abused, if it falls into the wrong hands.

“Oftentimes police will deploy these technologies without any consultation with the public,” said Camilla Graham Wood, legal officer of Privacy International, which advocates for human rights as digital surveillance grows. “They’re relying on older, outdated laws that came into being long before these technologies were even considered… So, it is unclear what legal basis they are relying upon.”

Some of the fingerprint technology relies on paper-spray mass spectrometry, a method already in use by airport security to detect explosives.

“We chose paper-spray mass spectrometry because it’s gaining popularity in forensics because it is incredibly sensitive and very easy to set up a testing system,” said Catia Costa, an analytical chemist and liaison fellow at the University of Surrey’s Ion Beam Center. “It’s been well known over the past few years that you can tell what people have ingested based on the sweat secreted at their fingertips” that contain telltale metabolites “which suggest the cocaine has been through the body.”

The tests, which are described as working similarly to home pregnancy tests, come in variations that detect different classes of drugs.

“One detects opiates, another detects amphetamines, another detects cocaine, and another THC, which is the active ingredient in marijuana,” explained Jerry Walker, CEO and chemist at Intelligent Fingerprinting, the company that co-funded the research.

Walker envisions the product doing more than just testing for relapse in addiction recovery patients.

“We think our technology would be a very good deterrent because prison authorities could walk into a cell at any time” to conduct drug tests, Walker said. “You could potentially sweep an entire prison wing within hours as opposed to days or months.”

Similar technology helped close a previously cold case by finding traces of blood in a 30-year-old fingerprint. But despite these benefits, some are concerned.

“There are serious ramifications associated with using biometric applications to collect data on drug use among people with [limited] consent. This concerns me because it has the potential to be widely adopted,” said medical ethicist Glenn Ellis. “Who has access to that information? Does that private employer have the right to share that information with future employers, law enforcement, and insurance companies?”

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Bryan Le grew up in the 90's, so the Internet is practically his third parent. This combined with a love for journalism led him to The Fix. When he isn't fulfilling his duties as Editorial Coordinator, he's obsessing over fancy keyboards he can't justify buying. Find Bryan on LinkedIn or Twitter