The Future of Gut Testing: Just Breathe! Researchers at WashU Medicine have discovered a way to measure the gut microbiome through breath analysis. How? Gases produced by gut bacteria enter the bloodstream and are exhaled through the lungs. The Result: No more stool samples needed to track asthma, obesity, and digestive health. The Vision: Soon, monitoring your microbiome will be as simple as blowing into a breathalyzer. Goodbye invasive tests, hello real time biodata.