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A "breathalyzer" test given to critically ill patients helped detect COVID-19, a small clinical validation study found.

The test detected COVID-19 with 88% sensitivity among a group of 46 patients admitted to the ICU, 23 with COVID infection and 23 without, reported Pelagia-Irene Gouma, MD, of the Ohio State University in Columbus, and colleagues in .

The test had a specificity of 83%, a positive predictive value of 78%, and a negative predictive value of 90%. Its accuracy was 85%, the authors said.

Interestingly, they noted that the sensitivity of PCR detection platforms for SARS-CoV-2 ranges from 71% to 98%.

Gouma and colleagues explained that the test detects a "breath print" unique to COVID-19, based on the amount of oxygen, ammonia, and nitric oxide. Gouma said in a statement that the technology uses nanosensors to detect specific biomarkers in the breath.

"This is the first study to demonstrate the use of a nanosensor breathalyzer system to detect a viral infection from exhaled breath prints," she noted.

The authors added that traditional molecular testing for COVID has "low detection accuracy" for early disease, and "persistent positive results after an infection has resolved."

For this study, they examined data from patients admitted to the ICU for acute respiratory failure who required mechanical ventilation. All patients were tested for COVID-19 prior to admission. Patients breathed into a "breath bag" on days 1, 3, 7, and 10 of their ICU stay.

The authors found a distinct pattern to the interaction of oxygen, ammonia, and nitric oxide in COVID-19 infection, which they dubbed the "Omega pattern" due to its resemblance to the Greek letter.

They then attempted to validate the results in a cohort of 46 patients. COVID patients were younger than non-COVID patients (median age 61 vs 65, respectively), with more men (61% vs 48%). Those with COVID-19 had a significantly higher rate of diabetes versus those who did not (52% vs 22%). Seven patients were excluded for a total of 39 patients.

On day 1, 14 patients in the COVID-19 group had the "Omega" breath pattern versus four in the control group. Nineteen in the control group had a non-Omega pattern compared with two in the COVID group.

Limitations to the data included its small sample size, the fact that the patients likely represented the most severe cases of COVID-19 pneumonia, and patients were not screened for other viruses.

Gouma and colleagues said that they hope to study this technology in other diseases or infections, or to see if it could be used earlier in the COVID disease course.

"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," said co-author Matthew Exline, MD, also of the Ohio State University, in a statement.

The researchers have applied to the FDA for emergency use authorization for this breath test, according to a press release.

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