Analyzing the air exhaled by the patient seems to be a promising avenue for detecting Covid-19.
- The analysis of exhaled air seems to be a promising avenue for the detection of Covid-19.
- It detects infections caused by the Delta variant with an efficiency of 94.7%.
- After new research on the Omicron mutation, the test was also able to detect this form of the coronavirus with an efficiency of 90.9%.
In the majority of cases, Covid-19 is detected by a PCR test-type nasopharyngeal swab. And, admittedly, this review is far from pleasant. Researchers at the University of Michigan have found a simpler and above all less invasive screening method for the patient: the analysis of expired air.
Breath analysis to identify Covid-19
To check whether it was possible to diagnose Covid-19 with breath analysis, scientists analyzed 205 samples of exhaled air from 167 patients in the intensive care or emergency room of the American university hospital: 77 were taken in charge for Covid-19 and 91 for another disease. Some volunteers performed the exam several days apart.
Overall, 94 samples tested positive for Covid-19: 41 came from patients infected with the Delta variant or other mutations and 53 came from patients affected by Omicron. The researchers found that four volatile organic compound (VOC) biomarkers were able to differentiate Covid-19 caused by the Delta mutation from other diseases with 94.7% accuracy. With the Omicron mutation, the efficiency dropped to 82.1%.
The team then worked to identify VOC biomarkers specific to the new strain. Four specific new elements have been spotted. They made it possible to diagnose Covid-19 caused by Omicron from another infection with an accuracy of 90.9%. “Breath analysis distinguished Omicron from previous variants with 91.5% accuracy and Covid-19 (all SARS-CoV-2 variants) from non-Covid-19 disease with 90% accuracy. .2%”add the authors in their article published in the journal Jama Network Openon February 28, 2023.
Pursue research for more effective screening tests
The air exhaled by the volunteers was analyzed by gas chromatography (GC). This is a technique which makes it possible to separate volatile molecules from a gaseous mixture.
“The results of this study suggest that analysis of exhaled breath using GC may be a promising method for detecting Covid-19 and similar diseases resulting in the production of VOCs”, say the authors. However, they acknowledge: “During our study, we noted a significant decrease in sensitivity (from 88.2% to 60.4%) from mid-January 2022. It was during this period that the Omicron variant became the dominant strain”.
Thus, as with other diagnostic modalities, such as rapid antigen tests, the emergence of new mutations is proving to be a challenge for healthcare professionals. This is why, according to the scientists, it is important to maintain investments and research in order to improve the efficiency of diagnostics.
