Xinhua News Agency, Beijing, April 24 (Reporter Peng Qian) No need to stab the throat or nose with a cotton swab, just pick up the straw and blow on the instrument, and you can find out whether you are infected with the new crown in 3 minutes-Recently, American food and For the first time, the Drug Administration authorized emergency use of a respiratory sample-based COVID-19 diagnostic test.

The test equipment is only the size of a carry-on suitcase and can detect exhaled air, which is more convenient and faster than PCR nucleic acid detection of nasopharyngeal swabs.

What is the principle of "breathing" to test the new crown

　　The FDA said in a press release that the device can perform tests in settings such as doctor's offices, hospitals and mobile testing sites.

A study of a total of 2,409 people including people with new crown symptoms and asymptomatic infections showed that the device detection sensitivity was 91.2%, and the specificity was 99.3%.

Results from studies specifically targeting the Ormicon strain showed similar device detection sensitivity.

　　Professor Yao Maosheng, head of the Bioaerosol Laboratory of the School of Environmental Science and Engineering, Peking University, said that compared with the existing PCR nucleic acid and antigen tests, the new crown breath test can quickly detect early infection, asymptomatic infection, etc., reducing waiting time ; The acquisition of samples is simple and non-invasive, which greatly reduces the discomfort of collecting nasopharyngeal swabs before; the cost of a single test is also significantly reduced.

　　According to the US FDA press release, the new crown breath analyzer approved for emergency use this time uses gas chromatography-mass spectrometry technology to separate and identify compounds in exhaled breath. A volatile organic compound is used to determine whether it is infected with the new crown, and the whole process takes less than 3 minutes.

　　Yao Maosheng said that human exhaled breath contains a large number of disease-related compound markers, so diseases including new coronary pneumonia can be quickly diagnosed by detecting the markers in exhaled breath.

Exhaled volatile organic compounds have been used in cancer, diabetes, chronic obstructive pulmonary disease and other diseases research in the past.

A study published in the British medical journal "The Lancet" showed that the breath of people infected with the new crown contains substances such as aldehydes, ketones and alcohols. After being infected with the new coronavirus, these volatile organic compounds present a specific combination.

　　The equipment approved for emergency use this time was developed by InspectIR in the United States. It is expected to produce about 100 units per week, and each unit can evaluate about 160 samples per day.

　　Jeff Schullen, director of the FDA's Center for Devices and Radiological Health, said that this authorization is another example of rapid innovation in new crown diagnostic tests. possible future public health emergencies.

　　However, the US Food and Drug Administration reminded that samples tested positive by the new crown breath analyzer should also be further confirmed by nucleic acid testing.

Negative samples need to be judged based on the subject's recent contact history, disease history, and whether they show clinical symptoms of the new crown.

Test results should not be used as the sole basis for patient treatment or management decisions, infection control.

Can be used as a useful supplement for nucleic acid detection

　　The "breath" test of the new crown has become an auxiliary detection method for promotion and application in many countries due to its unique advantages.

In May last year, a breath-testing device developed by Breathhonix, a spin-off from the National University of Singapore, was approved by the Health Sciences Authority of Singapore.

The company claims the device can detect whether a person is infected with the new coronavirus within a minute, and the results of an initial clinical trial in Singapore showed an accuracy rate of more than 90%.

In addition, Israel, Indonesia, the Netherlands and other countries have also launched similar new crown breath tests.

　　Yao Maosheng said that in the early days of the outbreak, his research group developed a non-invasive exhaled breath screening system, and related papers have been published in the British Journal of Respiratory Research.

Model tests show that the system has a specificity and sensitivity of over 95%.

Recently, the team has developed a second-generation device that costs about 2 yuan for a single test and reduces the test process to 30 seconds.

The team is further testing COVID-19 patients and healthy people with the second-generation products to optimize the detection efficiency and sensitivity.

　　At present, the new crown epidemic is still ongoing in many parts of the world, and rapid screening is essential to contain the pandemic and restore normal social life.

Yao Maosheng believes that the high efficiency of breath detection can effectively make up for the shortcomings of nucleic acid detection in some occasions, such as large-scale rapid preliminary screening of close contacts and high-risk groups, especially for some occasions where rapid judgment is urgently needed.

"In closed communities, buildings, junctions with epidemic control, emergency diversion, etc., the use of such equipment can achieve rapid pre-screening, reduce prevention and control costs, and ensure normal traffic and life," Yao Maosheng said.

　　John Redmond, co-founder and company president of InspectIR, also said that the need for rapid, centralized testing for work environments is increasing during the epidemic.

If you put a breath test device in the office, employees can go to work like a "work check-in" before going to work, and get a negative result in 3 minutes before going to work, which can effectively prevent clustered epidemics.

　　Experts believe that breath testing can also "find gaps and fill leaks" for nucleic acid testing.

Conventional nucleic acid and antigen tests are difficult to effectively avoid the interference of antigen cross-reactions on test results, and are prone to false positives or false negatives.

The device is a targeted detection of volatile organic compounds related to new crown infection, with high sensitivity, and can further screen suspicious people among people with negative nucleic acid tests, so as to achieve "double insurance".

In addition, places that do not have nucleic acid detection conditions can also use this technology as a supplement.