That success justified testing Cliff’s sense of smell around patients in a hospital, and indeed he correctly identified 25 of 30 people who were sick with the infection and also identified 265 of 270 people who were not sick — a remarkable rate of accuracy for a diagnostic tool that’s almost instantaneous and completely noninvasive. It’s also encouraging since Cliff was trained to detect even the slightest presence of
C. difficile
, wafting in the air from a wooden stick, piece of fabric or plastic vial carrying the bacteria.