New test spots drug use from single fingerprint

Scientists have developed a new, non-invasive test that can detect cocaine use through a simple fingerprint.

The new fingerprint method can determine whether cocaine has been ingested rather than just touched.

"The beauty of this method is that not only is it non-invasive and more hygienic than testing blood or saliva, it cannot be faked," said Melanie Bailey from the University of Surrey.

By the very nature of the test, the identity of the subject is captured within the fingerprint ridge detail itself, he added.

For the results, a team of researchers used different types of an analytical chemistry technique to analyse the fingerprints of patients attending drug treatment services.

They tested these prints against more commonly used saliva samples to determine whether the two tests correlated.

While previous fingerprint tests have employed similar methods, they have only been able to show whether a person had touched cocaine, and not whether they have actually taken the drug.

When someone has taken cocaine, they excrete traces of benzoylecgonine and methylecgonine as they metabolise the drug and these chemical indicators are present in fingerprint residue.

"We sprayed a beam of solvent onto the fingerprint slide to determine if these substances were present," Bailey added.

It is anticipated that this technology could see the introduction of portable drug tests for law enforcement agencies to use within the next decade.

The research was published in the journal Analyst.