We're all unique snowflakes, as evidenced by our fingerprints. But our prints and DNA are not the only features individualized to each of us. New research shows that our breath, too, can be used as an unique identifying feature, thanks to the varying assemblies of internal microbes that inhabit our bodies.

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To discover these unique “breathprints,” ScienceNOW reports, scientists recruited volunteers to blow into a mass spectrometer, a machine often used in chemistry to separate chemical components of different samples. Within seconds, the mass spectrometer spit out results for each person. These breathprints not only vary between individuals, the researchers found, but also change throughout the day within individuals in reflection of shifting chemical reactions within the body. But a unique core signature always underlies a person’s breath, to the point that it could be used to identify the individual participants in the study.

In the future, breathprints could become the new urine tests, the researchers think. Breathprints couple be a more surefire way to tease out drugs a person may be taking, or to find out whether an athlete is doping, bringing a new meaning to the term “bad breath.”

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