Heroin and cocaine commonly found on fingerprints of non-users

Researchers from the University of Surrey have revealed how widespread drugs have become in our environment. More than one-tenth of individuals they observed in a study had traces of drugs they had never used on their fingerprints.

As a result of their investigation, the experts developed a method of determining the difference between people who have used cocaine or heroin and those who have simply been exposed to the drugs somewhere in their surroundings. The technique works even if individuals have washed their hands.

The research team tested the fingerprints of 50 drug-free individuals and 15 participants who had used either cocaine or heroin in the previous 24 hours.

Even though they had no history of drug use, cocaine was found on 13 percent of the drug-free individuals and heroine was detected on one percent.

“Believe it or not, cocaine is a very common environmental contaminant – it is well known that it is present on many bank notes. Even so, we were surprised that it was detected in so many of our fingerprint samples,” said study co-author Dr. Melanie Bailey.

The researchers found that cocaine and heroin can be transferred through a handshake. This experiment enabled the experts to identify a cut-off level that can be used to accurately distinguish between drug use and secondary transfer.

“By establishing a threshold for significance on a fingerprint test, we can give those tested the piece-of-mind of knowing that whatever the result of the test may be, it was not affected by their everyday activities or shaking hands with someone that had taken drugs,” said Dr. Bailey.

“It’s clear that fingerprint testing is the future of drug-testing,” said lead author Mahado Ismail. “There are many factors that set fingerprint testing apart – it’s non-invasive, easy to collect and you have the ability to identify the donor by using the sample. Our study will help to add another robust layer to fingerprint drug testing.”

The study is published in the journal Clinical Chemistry.

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By Chrissy Sexton, Earth.com Staff Writer