Breath compounds could make it easy to detect COVID

The emergence of new COVID-19 variants have made rapid testing methods less accurate. A recent study suggests that a patient’s breath might hold the key to a more precise diagnosis.

Investigators from the University of Michigan Max Harry Weil Institute for Critical Care Research and Innovation used portable gas chromatography to examine breath samples collected during the pandemic’s Delta surge and its transition to Omicron (from April 2021 to May 2022).

The results showed that gas chromatography technology (GC technology) can diagnose COVID-19 with a high level of accuracy. It was also found that the volatile organic compounds in the breath of patients with Omicron differed from patients with earlier variants. These were molecular-level differences which could be used to distinguish between COVID-19, its variants and non-COVID illnesses.

“Exhaled breath contains hundreds of VOCs, which the body produces in response to infection and inflammation,” said study author Dr. Xudong (Sherman) Fan. “Early in the pandemic, we used GC technology to discover and define sets of VOCs for detecting COVID-19. However, we needed to gain a better understanding of how dynamically emerging variants impact this technology.”

The research team conducted a diagnostic study of 167 patients and collected 205 breath samples in 3 cohorts:

• COVID-19 (2021): Patients with COVID-19 assumed to be infected by Delta or earlier variants
• COVID-19 (2022): Patients with COVID-19 assumed to be infected by the Omicron variant
• Non-COVID-19 illness as well as patients who have recovered from a COVID-19

Using a novel point-of-care GC device developed by Fan and the team, the investigators defined four sets of VOCs that were able to distinguish between COVID-19 (2021) and non-COVID illness with an accuracy of 94.7 percent. However, when the team applied the same VOCs in a setting of presumed Omicron, sensitivity decreased drastically to 60.4 percent.

“We already knew clinically that different strains of SARS-CoV-2 can act quite differently,” said study co-author Dr. Robert Dickson. “This decrease in performance supports our suspicion that their effects on lung biology are quite different as well.”

The team undertook additional analysis and defined new VOCs to discern between Omicron and Delta, Omicron and non-COVID illness, and between patients with COVID-19 and non-COVID illness.  This combined analysis resulted in the ability to detect COVID-19 infected patients from non-COVID patients with an accuracy of 90.2 percent. This method is close to RT-PCR tests and better than many rapid antigen tests.

This study presents a promising new method for detecting COVID-19 and other diseases. Further analysis will be needed to determine how to use breath analysis to improve the diagnosis and care of patients.

“The fact that we were able to diagnose COVID-19 in both symptomatic and asymptomatic participants is encouraging,” said Dr. Fan. “More studies on these particular VOCs, including their origins, may assist in the development of a better understanding of COVID-19 as well as the potential to develop new diagnostics.”

The portable GC technology is now licensed for commercialization where further work is seeking to develop the technology for the diagnosis and monitoring of other diseases that produce VOCs due to inflammation. The research is published in the journal JAMA Network Open.

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By Katherine Bucko, Earth.com Staff Writer

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