One day, a machine will smell whether you’re sick

Blindfolded, would you know the smell of your mom, a lover or a co-worker? Not the smells of their colognes or perfumes, not of the laundry detergents they use — the smells of them?

Each of us has a unique “odorprint” made up of thousands of organic compounds. These molecules offer a whiff of who we are, revealing age, genetics, lifestyle, hometown — even metabolic processes that underlie our health.

Ancient Greek and Chinese medical practitioners used a patient’s scent to make diagnoses. Modern medical research, too, confirms that the smell of someone’s skin, breath and bodily fluids can be suggestive of illness. The breath of diabetics sometimes smells of rotten apples, experts report; the skin of typhoid patients, like baking bread.

But not every physician’s nose is a precision instrument, and dogs, while adept at sniffing out cancer, get distracted. So researchers have been trying for decades to figure out how to build an inexpensive odor sensor for quick, reliable and noninvasive diagnoses.