This would be a great way to test for disease. Like Michio Kaku said, in 30 years, our bath mirror will have more diagnostic power, than any lab has today. You will simply breath upon your bath mirror and it will tell you, if you are ill, have infections or cancerous cells in your body. These studies lay the basis. http://www.wired.co.uk/news/archive/2013-04/4/breathprint[ Everyone's unique metabolic phenotype -- a measure of overall health -- is present in his or her exhaled breath, a study has suggested. This "breathprint" could pave the way for personalised medicine with a simple, non-invasive breath test detecting all manner of health indicators instantly. With the advent of human genome mapping, personalised healthcare has been at the forefront of medical research. However, the ETH Zurich University team behind the PLOS ONE study is flagging up the technology's practical limitations in the face of other factors that contribute to health, including lifestyle, interplay with the gut microbiome and our circadian cycle. "For this reason," write the authors, "mapping of the metabolome and relating it to sub-populations or even individuals will be critical to fully achieve the concept of personalised healthcare". Basically, it's not enough to customise drugs to an individual's genetics -- we need to know all the factors contributing to their health and see the bigger picture. The metabolome refers to a complete collection of metabolites containing health-defining biofluids. If we can work out whether this remains stable over time in a person, we can verify the existence of "breathprints", thus making it easier to identify abnormalities visible as peaks and troughs in specific metabolite levels. And that's exactly what the Zurich team did... A separate US study also published in March demonstrated that the method could be used to identify patients suffering from heart failure with 100 percent accuracy. Speaking to the BBC, coauthor on the PLOS ONE paper Renato Zenobi said he did not understand why breath diagnosis is not already being more widely used. "In traditional Chinese medicine, they feel your pulse, look at your tongue and smell your breath. There are trained dogs who can sniff cancer with a fairly good hit-rate -- but the dog doesn't tell you what the compounds are." The hope is that the team has the time and opportunity to better understand the compounds that make up the breath, to one day deliver unique treatment solutions for everyone. Instantly.