XUE LI / ETH ZURICHEvery individual has a signature composition of metabolites—or compounds produced by chemical reactions in the body—in their exhaled breath, according to a study published this week (April 3) in PLOS ONE. These unique “breathprints” could one day be used in addition to blood or urine tests to reveal biomarkers of disease or test athletes for doping.
Previous work indicated that the presence of infections or even cancer might be detected in breath, but it was not clear whether the metabolic contents of breath varied enough between individuals, and whether each individual’s breathprint remained stable enough over time, to make it a genuine candidate for diagnostic use. To find out, a group of researchers led by Renato Zerobi of the Swiss Federal Institute of Technology in Zurich got 11 volunteers to blow into a mass spectrometer, which almost instantly parsed the exhalation into its chemical components.
Although each person’s breathprint changed slightly from sample to sample over the course of nine days of testing, the researchers observed that every volunteer had a chemical signature that was stable and specific enough to identify them. The findings suggest that like blood and urine samples, breath samples are reflective of the body’s internal chemistry and could therefore be used for metabolomic studies. Indeed, the fact that the method is non-invasive and produces results almost immediately makes it particularly appealing.
For the moment, however, the researchers still need to work out exactly what the chemical readings of breath can tell us. “We're at the onset of learning about what the compounds are,” Zenobi told BBC News. “Just a small fraction of the peaks that we see are identified at this point, so there's a lot of footwork to be done.”