Breath tester: An engineer at Metabolomx breathes into a breath-analysis machine.
Peter Mazzone, a pulmonologist at the Cleveland Clinic, who is running clinical trials of the new system, says a noninvasive metabolic breath test could help doctors make a better decision when a CT scan looks suspicious. Today, when doctors find a nodule in a patient’s scan, they have to follow up periodically to see if the nodule gets bigger, and then do a biopsy. And eventually Mazzone hopes a metabolic breath test could help predict the behavior of a particular cancer and what drugs it will respond to: “How aggressive is it? Do we need to simply remove it, or remove it and give chemotherapy?”
In the current version of the system, a patient must breathe through a tube for about five minutes. Pumps draw the breath through a series of filters to dry it out and remove bacteria, then over an array of sensors. Metabolomx has shown that the system can distinguish breath samples from patients with different subtypes of lung cancer.
The sensor array consists of colored reactants that are each sensitive to a different group of volatile compounds. Depending on what’s in the sample, different spots in the array—24 in the version used for the initial clinical trial, 130 in the current one—will change color to varying degrees. The system takes a photo of the array of colored reactants before and after they’re exposed to the breath sample, subtracts one image from the other, and generates a colored pattern for that sample.
Rhodes expects a test to cost $75. Also, because it’s not specific to a particular group of chemicals, the Metabolomx sensor could, in theory at least, be used to screen for any disease that has a metabolic breath signature—the company is currently exploring tests for other diseases, including tuberculosis. “A breath signature could give a snapshot of overall health,” Rhodes says.