A study has find that about one in 10 people may have traces of class A drugs on their fingermark despite not take in them , but it ’s possible to differentiate them from those that have .

The study from the University of Surrey , published inClinical Chemistry , quiz the fingerprint of 50 volunteers who said they had not used drugs and about 25 who had convey cocaine or heroin in the past 24   hours .

Of those who were drug - free , about 13 percent had traces of cocain on their fingerprint and 1   per centum had a trace of heroin , even after washing their hands . But by setting a cut - off level , the researcher could tell who had plainly been exposed to the drug in the environment and those who were active users .

" Believe it or not , cocaine is a very plebeian environmental contamination – it is well known that it is present on many bank annotation , ” Dr Melanie Bailey , from the University of Surrey , say in astatement . “ Even so , we were surprised that it was detected in so many of our fingerprint samples . ”

The test was done by putting their fingerprints on chromatography paper and then extracting substances from them with solution , which were then analyzed . trace of the class A drug were found on the aforementioned 13 percent of non - drug users .

The investigator also tested the possibility that drug could be reassign via a handshake , with the drug - free volunteers asked to throw off the manpower of the drug users . Fingerprints taken after did show traces of the drugs , suggest   they can   be transferred , but it was still possible to tell the difference between the two grouping .

There were a duad of limitations with the study , notably that the sampling size was somewhat small and that all the military volunteer derive from the same locale of Surrey in the UK .

But Dr Bailey narrate IFLScience that it still essay their conception . And this same squad haspreviously shownthat researchers can practice fingerprint to   differentiate within moment whether a someone has used cocain .   The mental testing is especially enticing because it is non - encroaching , hygienic , and ca n’t   be duped . fingermark can also quickly be attribute to an somebody .

" fingerprint provide a really convenient way of screening for drug utilisation , " Dr Bailey tell IFLScience . " We foreknow the tryout will be used in workplace testing or for the renewal of drug users . "

In England and Wales , it ’s estimated that about2.7 million peopleaged 16 to 59 took illicit drugs in 2015 and 2016 , with more than 8,500 taken to infirmary with drug - related mental health disorders and 2,500 deaths from drug misuse .