Tuberculosis (TB) is still a killer in developing countries with one of the primary hurdles to controlling disease spread being a fast, cost-effective diagnostic tool. Draper Laboratories (Cambridge, Massachusetts) is about to start a human trial to test a hand-held, point-of-care TB testing device that has already been used for several years by the military in biodefense applications.

"We see that in the future Differential Mobility Spectrometry (DMS) will eventually be able to determine if someone is infected with TB just by exhaled breath, but that's in the experimental stage. What we're working on now is to identify TB from sputum," Jose Trevejo, MD, senior biomedical scientist, Bioengineering Division at Draper, told Medical Device Daily. "A lot of infections are detected using ELISA. But there's something about TB's biology that the standard approach of using antibody detection doesn't work well. We've come up with a new approach to detect the biomarkers."

The Centers for Disease Control and Prevention (CDC; Atlanta) reports that more than nine million people get sick each year with the TB bacteria that usually attacks the lungs and almost two million die. The tests currently available to diagnose TB are a sputum culture, a skin test and a blood test, all of which require trained healthcare workers, special lab equipment and the need for patients to return for a follow-up.

"I think the DMS would have a huge impact on the global TB situation," Trevejo said. "There's a huge need. I went to an international meeting last year and physicians there told me they have a lot of problems diagnosing TB. The gold standard that's more sensitive, a culture, takes one to three weeks, is expensive and requires an advanced facility. Most of the time it's not feasible, testing takes too long and they lose the patient in follow-up. They need something rapid. This could be a paradigm-shifting technology."

The DMS technology is currently used by the military and through a license to Sionex (Bedford, Massachusetts).

"It's a MEMS [microelectromechanical systems] chip that's the size of a dime. It has a small sensor," he said. "When you introduce volatiles, it detects ions. Fully assembled prototypes are as small as a deck of cards."

He explained that the DMS technology is different from electronic noses, which work by pattern recognition.

"This is more like mass spectrometry, the gold standard, and has similar sensitivities," he said. It rapidly analyzes volatile organic compounds (VOC) in the sputum or breath.

"To date we have identified over 16 VOCs associated with TB," he said. "For the initial development we focused on three compounds which were expressed in the highest amount."

Trevejo said Draper is collaborating with the University of Texas (Brownsville) to initiate a 25-patient study in Mexico within the next six months. If all goes well, a larger trial will be initiated. Upon clinical validation, his team will start the regulatory review process.

He speculated that the device, with an approximate one-year lifetime, would cost $1,000 to $2,000 and individual tests would cost as little as $1.

Trevejo said other teams around the world are working on point-of-care TB diagnostics, but, "We think our instrumentation is much more advanced. We have a good lead on the biomarkers and it will enable us to identify the bacteria with more sensitivity too. Our main advantage is that our devices are already portable, already sensitive and potentially point-of-care."

Lynn Yoffee, 770-361-4789; lynn.yoffee@ahcmedia.com