03-07-2025
Can a Face Mask Diagnose Kidney Disease?
A face mask with specialized sensors was able to detect chronic kidney disease (CKD) based on exhaled levels of ammonia and other metabolites, according to the results of an Italian study. Sensors for ammonia and other relevant molecules achieved a 93.3% true positive rate and 86.7% true negative rate in detecting kidney diseases, reported Corrado Di Natale, professor of electronic engineering at the University of Rome Tor Vergata, Rome, and coauthors in a paper in the American Chemical Society's ACS Sensors .
The study included 50 patients who had been diagnosed with CKD, alongside 48 healthy control individuals. Control participants were drawn from patients' family members and hospital staff at the same clinic.
The test used a breath sensor embedded in a standard face mask. The sensors consisted of coated silver electrodes with a conductive polymer commonly used in chemical sensors. The electrodes were placed between the layers of a disposable medical face mask, with wires attached to allow an electronic readout of exhaled gases. The sensor was designed to detect CKD-related metabolites, including ammonia, ethanol, propanol, and acetone.
The project involved people in several departments, including nephrology and electric engineering, Di Natale said. The goal was to make the device easy for medical staff and patients to use, not wanting to add a new complicated process for CKD testing, Di Natale added.
'It was actually very simple, very simple to use,' he said.
Expanding Breath Analysis
Di Natale told Medscape Medical News that his team plans to continue working on tools for the diagnosis of metabolic disorders and lung cancer via breath analysis.
Physicians long have known that CKD and other diseases such as diabetes can affect how breath smells. An emerging field, called volatolomics, or volatilomics, seeks to identify changes in the composition of chemical byproducts expelled normally through breath.
Diagnostics based on breath samples would offer an attractive advantage in ease of collection, but there are many hurdles that researchers would need to clear to bring a product like a breath-based CKD test to market, Paul J. Jannetto, PhD, president-elect of the Association for Diagnostics & Laboratory Medicine, Washington, DC, told Medscape Medical News .
While the research published in ACS Sensors suggests promise, additional validation studies in larger cohorts would be required, Jannetto said.
'These preliminary small-scale studies are just the first step,' explained Jannetto, who is also a professor of laboratory medicine and pathology and vice chair of practice laboratory medicine at the Mayo Clinic, Rochester, Minnesota.
One of the biggest challenges in efforts to develop breath-based diagnostics is addressing the sheer number of volatile organic compounds (VOCs) carried out of the body through exhalation, Jannetto noted.
More than 1400 VOCs have been linked to human breath. A single human breath contains hundreds of VOCs, representing various pathophysiological processes that alter a person's metabolic state, wrote Pritish Varadwaj of the Indian Institute of Information Technology Allahabad, Prayagraj, India, and coauthors in 2023 in Molecular Diagnosis & Therapy .
'Electronic Noses'
There's been a long-standing interest in developing breath-based tests, or 'electronic noses,' for lung cancer, including a 2003 paper from Di Natale and coauthors in the journal Biosensors and Bioelectronics . Researchers in the UK and China have also published recent reports detailing attempts to develop an e-nose.
Among the most developed projects in this field is an e-nose collection device currently in a clinical trial of about 119 patients. Gaetano Rocco, MD, of Memorial Sloan Kettering Cancer Center, New York City, the principal investigator for this study, said early results indicate the technology agreed with histopathologic results 86% of the time when assessing for lung cancer in very small nodules detected by a CT scan.
Further testing continues on the ability of this e-nose device 'to modulate its response according to different phases of the patient's clinical history — ie, to detect the response after treatment of thoracic cancers, irrespective of the type of treatment (surgery, chemo and immunotherapy),' Rocco told Medscape Medical News via email.
Successfully developing an e-nose would result in a technology to aid patients at a high risk for lung cancer, as it could 'guide the timing of the imaging, thereby avoiding multiple CT scans,' Rocco added.
'This would decrease costs and radiation exposure; in addition, the miniaturization of the technology will serve the purpose of allowing the patients to self-screen by breathing in the collection device in the comfort of their homes.'
Di Natale received financial support from the European Union-NextGenerationEU (project ECS 0000024 Rome Technopole). Rocco and coauthors received support from National Institutes of Health/National Cancer Institute Cancer Center Support Grant P30 CA008748 and Memorial Sloan Kettering's Fiona and Stanley Druckenmiller Center for Lung Cancer Research. Rocco reported having a financial interest with Scanlan International, Merck, and Medtronic. Further author disclosures are available in the text of the paper.
