Beyond the Breathalyzer

Researchers are mining our exhalations to diagnose disease

Anyone who's ever had a few too many drinks knows that a little exhalation can reveal a lot of information. But the alcohol Breathalyzer, it turns out, was just the beginning.

A new batch of studies suggests that breath tests--exhaling into a medical sensor for analysis--can effectively screen for lung cancer, infections, diabetes and more. Although researchers have long known that those diseases alter our bodies' chemical makeup, they're starting to pinpoint the specific ways each alters our breath. Lung-cancer tumors, for example, produce a suite of volatile organic compounds that we wind up exhaling. "We're starting to discover so many...