University of Surrey researchers have developed an experimental fingerprint test that can identify traces of cocaine on human skin.

The test is smart enough to tell whether an individual has consumed the drug or merely handled it.

A fingerprint drug test from Intelligent Fingerprinting is already available. The test uses lateral flow assay technology with fluorescence-labelled antibodies to selectively detect specific drugs or their metabolites in eccrine sweat collected from fingerprints.

The new research demonstrates that this kind of testing is also possible using high resolution mass spectrometry.

The researchers took fingerprints from people seeking treatment at drug rehabilitation clinics who had testified to taking cocaine in the previous 24 hours. Two sets of fingerprints were taken from participants, both before and after they thoroughly washed their hands. The same process was then used to collect samples from a pool of non-users who had touched street cocaine. Oral samples were also taken from the participants.

The samples were then analysed using a high resolution mass spectrometry method to cross-reference the information from non-users and those who had testified to using the drug.

Researchers found that benzoylecgonine (BZE), cocaine’s primary metabolite, could be detected in the fingerprints of both groups after their contact with cocaine. However, after hand washing, the chemical could only be detected if the person had actually taken the drug.

Provided donors wash their hands before sampling, BZE levels can therefore be used to distinguish cocaine contact from cocaine ingestion.

Intelligent Fingerprinting chief scientific officer Dr David Russell said: “This University of Surrey laboratory study into cocaine testing using experimental high resolution mass spectrometry techniques validates the approach Intelligent Fingerprinting took when originally commercialising our portable fingerprint-based drug screening system for use at the point-of-care.”

Outside of drug testing, the research team hope to use the technology to try and detect pharmaceutical drugs in fingerprints, to help patients check that their medication is being delivered at the right dose.