Researcher Perena Gouma and her team at Stony Brook University (New York, US) are hoping that eventually their device will be available over the counter so anyone will be able to perform a preliminary diagnostic test as casually as you take a breath. From the May 7, 2012 news item on Nanowerk,

You blow into a small valve attached to a box that is about half the size of your typical shoebox and weighs less than one pound. Once you blow into it, the lights on top of the box will give you an instant readout. A green light means you pass (and your bad breath is not indicative of an underlying disease; perhaps it’s just a result of the raw onions you ingested recently); however, a red light means you might need to take a trip to the doctor’s office to check if something more serious is an issue.

Here’s a bit more about the device and the researchers’ hopes in a video from the US National Science Foundation (NSF) featuring the NSF’s Miles O’Brien as the reporter,

O’Brien in his May 7, 2012 article for the NSF’s Science Nation online magazine describes the technology,

With support from the National Science Foundation (NSF), Professor Perena Gouma and her team at Stony Brook University in New York developed a sensor chip that you might say is the “brain” of the breathalyzer. It’s coated with tiny nanowires that look like microscopic spaghetti and are able to detect minute amounts of chemical compounds in the breath. “These nanowires enable the sensor to detect just a few molecules of the disease marker gas in a ‘sea’ of billions of molecules of other compounds that the breath consists of,” Gouma explains. This is what nanotechnology is all about.

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The manufacturing process that creates the single crystal nanowires is called “electrospinning.” It starts with a liquid compound being shot from a syringe into an electrical field. The electric field crystallizes the inserted liquid into a tiny thread or “wire” that collects onto an aluminum backing. Gouma says enough nanowire can be produced in one syringe to stretch from her lab in Stony Brook, N.Y. to the moon and still be a single grain (monocrystal).

“There can be different types of nanowires, each with a tailored arrangement of metal and oxygen atoms along their configuration, so as to capture a particular compound,” explains Gouma. “For example, some nanowires might be able to capture ammonia molecules, while others capture just acetone and others just the nitric oxide. Each of these biomarkers signal a specific disease or metabolic malfunction so a distinct diagnostic breathalyzer can be designed.”

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Gouma also says the nanowires can be rigged to detect infectious viruses and microbes like Salmonella, E. coli or even anthrax. “There will be so many other applications we haven’t envisioned. It’s very exciting; it’s a whole new world,” she says.

I think most (if not all) of the handheld diagnostic projects I’ve covered have been fluids-based, i.e., they need a sample of saliva, blood, urine, etc. to perform their diagnostic function. I believe this is the first breath-based project I’ve seen.