Scientists can already tell from people’s fingerprints if they’ve touched cocaine, but a new study goes one step further, showing that fingerprints can now also reveal whether a person has ingested the drug. The study, published in Analyst, may pave the way for simpler drug testing that doesn’t require urine or blood.

In a small study, a team of researchers analyzed the fingerprints of a handful of patients in drug treatment centers using a process called mass spectrometry. Someone who uses cocaine excretes components of metabolized cocaine called benzoylecgonine and methylecgonine. The study authors showed they were able to detect the cocaine components in the residue left by the patients’ fingerprints on glass through the mass spectormetry chemical analysis technique.

“These results provide exciting opportunities for the use of fingerprints as a new sampling medium for secure, non-invasive drug detection,” the researchers write in their study. “The mass spectrometry techniques used here offer a high level of selectivity and consume only a small area of a single fingerprint, allowing repeat and high throughput analyses of a single sample.”

If such a technique could be made portable, the researchers believe it could possibly provide a simpler and less invasive alternative to current drug testing.

Get our Health Newsletter. Sign up to receive the latest health and science news, plus answers to wellness questions and expert tips. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Contact us at letters@time.com.