The chemical signature in your breath is unique to you, and may even be as distinctive as your fingerprint. In fact, researchers think your "breathprint" could soon be used to determine your true identity, or diagnose you with an illness.
For years, medicine has relied on blood, urine, and tissue samples to monitor wellness and disease. These biological samples contain metabolites – leftovers from the biochemical processes that keep a body running – that can convey important information about a person's health. A given metabolite profile depends on a variety of factors: diet, infection, circadian rhythms, the microorganisms living in your gut. They all affect the type and quantity of chemicals present in your body's various organs and biofluids – including, it turns out, your breath.
When you exhale, you expel more than nitrogen, oxygen, argon and CO2. There are also metabolites. But here's the question: do the metabolite concentrations in expired air vary enough from person to person (and are they consistent enough within a single individual) to be diagnostically useful?
Recent findings suggest they do. In 2011, researchers proved that dogs can be trained to reliably detect lung cancer on the breath of hospital patients. Earlier this month, scientists demonstrated that a breath test could be used to diagnose stomach cancers with 90% accuracy. Now, research presented in the latest issue of the open access journal PLOS suggests that each and every one of us has a unique breathprint, providing some of the most compelling evidence to date that a person's breath can serve as a valuable (and minimally invasive) diagnostic tool.