November 12, 2024 | Recent years have seen progress toward developing tools that are designed to analyze a human breath sample to detect, diagnose, or monitor various health issues. Some of these efforts have focused on combating deadly infectious diseases, with intentions of creating cost-effective, easy-to-use breathalyzers capable of being deployed in rural, remote, and low-resource settings.
International Consortium Takes on Tuberculosis
A collaborative effort dubbed BreathForDx is aiming to develop, test, and put into practice novel breath-based methods for the diagnosis of tuberculosis. The intent is to develop two devices, optimize them, and evaluate the benefits of the diagnostic procedure in clinical trials.
The group announced its plans to study the extent to which this approach can detect drug resistance and learn how user-friendly and cost-effective the devices are compared to conventional methods. Beyond that, the consortium is looking to research how effectively breath-based diagnostics can help contain infection spread.
The European Commission and the Swiss State Secretariat for Education, Research and Innovation are funding the project. Collaborators include the IRCCS San Raffaele Hospital in Italy, the Desmond Tutu Health Foundation in South Africa, the Marius Nasta Institute of Pneumophthisiology in Romania, and the Swiss company Avelo.
Claudia Denkinger, medical faculty at Germany’s Heidelberg University and medical director of the Department of Infectious Disease and Tropical Medicine at Heidelberg University Hospital, is coordinating the project. “I am most excited about the accessible sample type that is easy to get and is likely to correlate much more with transmissibility,” Denkinger told Diagnostics World. “I think for viruses we can make it happen in the near term. For bacteria, like tuberculosis, where it would be groundbreaking to have a PCR based on breath, the paucibacillary nature of the sample is the biggest challenge.”
In a paper published in The Lancet Global Health (DOI: 10.1016/S2214-109X(24)00148-7), she and colleagues highlight diagnostic yield as a crucial metric for the evaluation of novel tuberculosis tests and argue it has yet to be sufficiently explored. The authors point out that diagnostic yield, defined as “the proportion of people in whom a diagnostic test identifies tuberculosis among all people we attempt to test for tuberculosis,” is especially relevant for populations unable to produce sputum, such as young children.
They also noted that diagnostic yield will continue to grow in importance as more accessible specimens like saliva, urine, and breath are pursued for tuberculosis testing. “Using more readily accessible specimens together with novel near-patient tests, including home-testing and self-testing, will improve diagnostic yield and coverage, especially in disadvantaged and vulnerable groups who are at the greatest risk of disease development and spread,” they concluded.
Funding Injections, Strategic Partnerships Bolster Device Development
For years, the Bill & Melinda Gates Foundation has implemented programs designed to reduce the transmission of malaria and tuberculosis, and in 2024 the organization has invested in a number of companies developing rugged, low-cost, disease-focused breathalyzers.
For example, Canadian-based Noze received new funding in the form of a $5 million equity investment that will enable additional development of its disease detection platform for use in low and middle-income countries. This latest round of support follows a previous grant from the Gates Foundation to fund a clinical study meant to detect tuberculosis in countries with a high burden of disease.
The company’s handheld diagnostic breathalyzer, called DiagNoze, uses odor perception technology to detect biomarkers in human breath. Noze leverages machine intelligence and sensors developed with licensed NASA technology and refers to its tool as a low-cost, non-invasive, and portable device.
Similarly, UK-based Owlstone Medical obtained recent financial support meant to advance the development of breath-based diagnostics for infectious diseases. The funding includes a $5 million equity investment from the Gates Foundation to advance the company’s Breath Biopsy platform. Work is expected to include the expansion of Owlstone’s Breath Biopsy VOC Atlas database and the development of a real-time breath analyzer that can be used remotely.
Another $1.5 million in grant funding is aimed at the discovery of breath biomarkers and will be used across two projects—one focused on tuberculosis and the other on HIV. Along with the University of Cape Town in South Africa, Owlstone is looking to identify a panel of VOC biomarkers that differentiate tuberculosis subjects from healthy controls and develop breath diagnostic approaches that rely on metabolic features. In collaboration with researchers at Imperial College and Oxford University, the company also plans to analyze VOCs from blood samples and come up with a panel of biomarkers associated with HIV viral load.
In addition to investing in Owlstone, Noze, and other companies, the Gates Foundation is working with government agencies to advance efforts in this space. The organization has partnered with the FDA’s Center for Devices and Radiological Health (CDRH) to develop new methods to accelerate the development of breath-based diagnostic devices for underserved groups. The project includes developing and validating an interactive database of healthy and infected breath that could be used to identify diagnostic biomarkers.
The establishment of a breath-print will enable the diagnostics community to identify disease biomarkers and facilitate the development of next-generation devices, according to a news release. The methods, including a web application for the analysis of mass spectrometry data, are meant to build confidence in measurement techniques and reduce risk for device developers and regulators alike.
The U.S. Department of Commerce’s National Institute of Standards and Technology (NIST) is also working with the Gates Foundation to come up with standards and protocols for a new generation of breathalyzers aimed at tuberculosis and malaria. Under the two-year, $2 million cooperative research and development agreement announced over the summer, NIST researchers will begin to create the standards, tools, and techniques needed to ensure that breathalyzers are reliable and accurate.
NIST’s Fluid Characterization and Gas Sensing Metrology groups will focus on two key goals. One main area of focus will involve testing equipment designed to benchmark performance and ensure accuracy. The other primary focus centers on gas mixtures for testing the accuracy of breathalyzers.
Kavita Jeerage, a materials research engineer at NIST, told Diagnostics World that this initial announcement marked the kickoff of a long-term validation effort that will continue for several years. She clarified that NIST is not developing breathalyzers but has gotten involved to create materials meant to validate their performance and help ensure the tools function as intended.
Complexity of Disease-Focused Breathalyzers
Jeerage highlighted the appeal of non-invasive diagnostics, which could lead to more comfortable and more frequent measurements. “I think that diagnostics that are non-invasive are so appealing because no one really loves getting their blood drawn,” she said. “No one loves having invasive processes to figure out what’s going on.” Any time a diagnosis or screening can move from an invasive or uncomfortable process to one that is non-invasive or more comfortable is a win in her view because more people will likely pursue that sort of measurement.
On the other hand, there are current limitations when it comes to tapping into the potential of breath-based tools. Matching multiple breath components for disease-focused breathalyzers is a notable hurdle. “I think there will be a challenge in terms of how many different components of breath we’re going to need to match in order to have a breath surrogate,” she said. That’s a big difference between a more simplistic type of breathalyzer and what may be the future of disease-focused breathalyzers.
“The analogy here is the alcohol breathalyzer,” she explained. “This is very mature technology.” It has been around for nearly a century in one form or another, Jeerage pointed out, although early iterations were simple compared to the devices used today.
The devices currently made for law enforcement purposes are calibrated with materials that mimic the breath of someone who is at various levels of impairment, and there are also quality control checks that can be done with these materials. “Those trace back to NIST standards,” she said, “and so our goal is to start developing these sorts of materials for disease breathalyzers.”
An alcohol breathalyzer focuses on a single molecule (ethanol) that is in a very high concentration when an individual is intoxicated. “You don’t need to mimic very much about breath,” she said. Ethanol and nitrogen can be put into a gas cylinder, and different quantities of ethanol can be used in that cylinder to generate different gasses used for testing, validating, and calibrating devices.
Disease-focused breathalyzers, on the other hand, are more complex. The concentrations of the molecules that will be detected are smaller with a disease-focused breathalyzer, Jeerage explained, and then there are all the other molecules that are exhaled just by living, breathing, and digesting food. Part of the challenge involves mimicking various breath components, including water, oxygen, and carbon dioxide, to create useful materials for validation.
For now, it isn’t clear to what extent all of that will need to be mimicked in this matrix-matched material. “We’re starting the process of trying to create materials in gas cylinders,” she said. Researchers are bottling a variety of compounds found in breath, including in disease scenarios, and then looking at the matrix matching aspect of it, which involves adding in the water, oxygen, and carbon dioxide content that is present in breath. The intent is to develop materials for disease breathalyzers, benchmark them, and identify sensor lifetimes and calibration frequencies.
Future Potential for Broader Applications
Jeerage pointed out that companies both large and small are working on developing breathalyzers focused on various challenges, and looking ahead, she hopes that breath-based tools meant to screen, diagnose, or monitor health issues will evolve to provide reliable measurements for clinical use. “Our goal is to give them tools so that they can test their devices and so that people who use these devices down the road—whether that’s the physicians or the people who are actually being tested—have confidence in what they’re seeing at the end of the day,” she said.
As she considers the future of breath-based tools, Jeerage acknowledged the need for input and collaboration from a variety of perspectives, including clinical physicians. “There are a lot of different kinds of expertise that I think need to go into making this successful,” she said. NIST is looking at one aspect, but others are focused on aspects like device development and conducting measurements in the field. There are many different pieces going into this effort and many different pieces to get right, but from her vantage point, this is ultimately “the path forward for success.”
While various breath-based efforts may initially be geared toward a specific disease or two, some see the potential to adapt standards, methodologies, or technologies to address other health issues. BreathForDx envisions the possibility of adapting its methods to other respiratory diseases, for example, and Jeerage noted that the standards NIST creates for tuberculosis and malaria breathalyzers could set the stage for broader applications in breath analysis.
Paul Nicolaus is a freelance writer specializing in science, nature, and health. Learn more at www.nicolauswriting.com.