INHALE, EXHALE, WAIT FOR RESULTS

After receiving a heart transplant in March, Michael Sinno endured painful monthly biopsies to make sure his body wasn't rejecting his new organ. In August, instead of going under the knife again, his doctor surprised him — by asking him to just breathe into a tube. The device sampled his breath, then a lab checked it for key chemicals that would indicate rejection.
The Los Angeles Times