A team led by researchers at the University of Surrey in the United Kingdom has developed a new, non-invasive test that's able to detect cocaine use in a patient by analyzing a single fingerprint. Unlike existing tests, the new technique is able to determine whether the subject has ingested the drug, rather than just touched it.

Drug testing is a common practice in prisons, courts and numerous other law enforcement agencies, but existing methods have significant limitations, often requiring specialist staff and off-site analysis. While not quite ready for mass introduction, the newly-developed technique could make things significantly easier. It's non-invasive, hygienic and impossible to fake, with the identity of the subject captured in the fingerprint itself.

The technique makes use of mass spectrometry to analyze patient fingerprints, searching for traces of the chemicals methylecgonine and benzoylecgonine, which are excreted by the body as the drug is metabolized. To look for these indicators in the fingerprint residue, a beam of solvent is sprayed onto the slide – a technique known as Desorption Electrospray Ionisation (DESI). The method has been used for other forensic applications in the past, but this is the first time it's been used to test for drug use.

The team believes that the technique could be introduced as a portable drug test for law enforcement agencies within the next 10 years.

"We are only bound by the size of the current technology. Companies are already working on miniaturized mass spectrometers, and in the future portable fingerprint drugs tests could be deployed," said the University of Surrey's Dr. Melanie Bailey. "This will help to protect the public and indeed provide a much safer test for drug users."

The research was conducted by a collaborative team from the University of Surrey (UK), National Physical Laboratory (UK), King's College London, Sheffield Hallam University (UK) and the Netherlands Forensic Institute.

The researchers published their findings in the journal Analyst.