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Experimental technology can 'smell' disease on your breath

Susan Scutti, CNN | 11/7/2017, 8:22 a.m.
Smell is a primary human sense, key to our survival.
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"Quick diagnosis can help in identifying the most appropriate treatment response," he said. He added that prostate cancer grows on a longer time-scale, but the prostate biopsy is such "a sufficiently unpleasant experience" that a noninvasive test would be beneficial and lower health-care costs.

The high accuracy claims of Haick's research group is "very reasonable, if the signal is not masked by environmental fluctuations in some manner," Agarwal said, though he cautions that some "breath-based tests have had difficulty duplicating results in different regions, likely because the sensor has difficulty adjusting to different background air signals."

Other scientists raise additional concerns.

Not ready for prime time?

Dr. George Preti, a faculty researcher at Monell Chemical Senses Center, a nonprofit scientific institute in Philadelphia, said it's hard to distinguish body chemicals from environmental chemicals in breath samples because "most of the compounds detected in breath are also detected in room air and their levels are similar to each other."

Until scientists "understand the origin and biochemical pathways leading to disease-related" markers in human breath, reliable results from a diagnostic breath test will be difficult to achieve, he stated in a recent review of studies.

In fact, there are more than a few issues that must be addressed before effective technologies will be produced, according to Dr. Lisa Spacek, an adjunct assistant professor at Johns Hopkins School of Medicine, and Terence Risby, professor emeritus at the Johns Hopkins University Bloomberg School of Public Health.

Using breath to diagnose disease first requires a profile of breath molecules for normal health to be established, Spacek and Risby say in a recently published paper. These must take into account variables such as age, gender, ethnicity and body mass index.

Researchers also need to investigate the factors that might contaminate breath results, such as what someone ate within eight hours of breath collection or whether they used a mouth rinse, say Spacek and Risby. Another issue: How do you store breath that is not immediately analyzed?

Advances in instrumentation, particularly portable monitors, is one factor inspiring and enabling the new research into breath analysis.

Though the field is growing and results are promising, translation of the work into meaningful tests is another matter: "I take every claim by manufacturers ... with a grain of salt," Risby wrote in an email.

Today's widespread interest in breath analysis stems from the relatively recent discovery -- within the past 20 years or so -- that nitric oxide, a common pollutant, works as a signaling molecule in the cardiovascular system, Risby observes. The three scientists who made the discovery won a Nobel Prize for their efforts in 1998.

So despite ancient roots, Risby says, "clinical breath analysis remains in its infancy."