Q&A: Breathalyzer for COVID-19 shows promise

A novel breathalyzer detected SARS-CoV-2 in critically ill patients with 88% accuracy, according to findings published in PLOS ONE.

The device is being developed at The Ohio State University Wexner Medical Center. It was designed by Pelagia-Irene Gouma, MSc, MPhil, PhD, the Edward Orton Jr. Chair in Ceramic Engineering and professor of materials science and engineering and mechanical and aerospace engineering at The Ohio State University, and Milutin Stanaevi, MS, PhD, an associate professor in the department of electrical and computer engineering at Stony Brook University.

Matthew Exline, MD, MPH, a pulmonary critical care physician and director of critical care at The Ohio State University Wexner Medical Center, and colleagues tested the breathalyzer on 46 patients in the ICU who had acute respiratory failure requiring mechanical ventilation, half of whom were infected with SARS-CoV-2. The researchers collected breath samples from the patients, which were then tested with the device in a lab.

The technology detected breath prints of COVID-19 within 15 seconds of an exhaled breath. The sensitivity of the test for ICU patients was similar to the sensitivity of PCR tests, which ranges from 71% to 98%, according to Exline and colleagues.

“PCR tests often miss early COVID-19 infections and results can be positive after the infection has resolved,” Exline said in a press release. “However, this noninvasive breath test technology can pick up early COVID-19 infection within 72 hours of the onset of respiratory failure, allowing us to rapidly screen patients in a single step and exclude those without COVID-19 on mechanical ventilation.”

The results further showed that the breathalyzer yielded a specificity of 83%, a positive predictive value of 78%, a negative predictive value of 90% and an overall accuracy of 85%.

If successfully developed, the breathalyzer may offer physicians and patients earlier results and more feasible implementation in low-resource areas while reducing medical waste, according to Exline.

Healio Primary Care discussed the emerging technology with Exline to learn more about its applications to primary care and its potential role for detecting other diseases.

Healio Primary Care: Could you briefly describe how the breathalyzer works?

Exline: The breathalyzer basically looks like a circuit board right now. What’s exciting about this technology, which my collaborator Dr. Gouma invented, is making these very thin, nano-arrayed chips detect different chemicals from the air. She has been working on this for the better part of 2 decades. The idea of using your breath to detect diseases is not new, but Dr. Gouma’s technology allows her to detect a lot of different compounds. She had been working on using this technology in patients who had the flu. When the pandemic first started, she approached us with the potential to detect patients who are infected with SARS-CoV-2.

We are still in the early phases of development. Eventually, physicians will be able to bring the device to a patient and have them blow directly into it. You can use the breath test multiple times. The idea is that this will be a good screening test, if nothing else. We now know that the breathalyzer works very well for people who are severely ill with COVID-19, and we are hoping to take it to patients who are not quite so sick. The goal is to make the device inexpensive enough to be cheaper than PCR testing. Also, the hope is that in the future, there are going to be a lot of diseases where we use a breath test instead of doing a blood test. The ability to do breath tests rapidly in a primary care setting or welfare or other low-resource areas would be pretty powerful. We are excited about its potential for COVID-19 but also its potential in the future for other diseases.

Healio Primary Care: You and your co-authors discussed in the study that the accuracy of the breathalyzer is comparable to PCR tests. Can you talk more about this?

Exline: Our test is a little below the public published accuracy of the PCR test. On the flip side, our test would be faster. We have had a lot of time, in general, to refine the PCR test and get it faster and better. Our hope is that as time goes by and we do more research, we are going to get the breathalyzer better as well.

People are usually most familiar with the alcohol breath test. That test is a good example because you can do it in the field. If you want a hyper-accurate test, you would still do a blood test, but the advantage of the breath test would be that it can be deployed into the field and be made available to patients or facilities directly.

Healio Primary Care: Did you observe any limitations with the breathalyzer?

Exline: There were a couple of false positives. A number of ICU patients had liver disease. Our detectors work by detecting nitrogen and ammonia, and we know liver disease affects your ability to process those gases, so we think that might have interfered. Also, there were a few false negatives. A few patients we said didn’t have COVID-19 did in fact have it, according to their PCR test. One of the false negatives occurred in a patient who had COVID-19 for quite some time, so we think they probably were out of the positivity window. The other patient with a false negative had a very mild case and was out of the ICU the next day, so we wondered if they didn’t have enough inflammation to register positive with the breathalyzer. This is where we need further research because our trial didn’t have enough patients to really explore all the different quirks in our patient population.

Healio Primary Care: What is the next step for this research?

Exline: We’ve done some work to try and use the breathalyzer with patients who are not as ill. That work is continuing. We are trying to look at patients who have been exposed to COVID-19 and then start testing them over time to see if we can tell when they first became positive. We are working with the university and going onto the next phase of the trial. This is exciting technology, and it has the potential to free us from having to be reliant on sticking something up your nose to test for COVID-19. Hopefully, in the near future, we will be able to get more information on how we can use it in areas outside of the ICU.

References:

Exline MC, et al. PLOS ONE. 2021;doi:10.1371/journal.pone.0257644.

Ohio State breath test can identify COVID-19 in critically ill patients. https://wexnermedical.osu.edu/mediaroom/pressreleaselisting/ohio-state-breath-test-can-identify-covid-19-in-critically-ill-patients. Published Oct. 28, 2021. Accessed Nov. 12, 2021.