Researchers studied the feasibility of using breath-analysis (pictured, stock image) to distinguish COVID-19 from other respiratory conditions, including influenza
United Kingdom (UK) scientists say a non-invasive breath test can identify people with coronavirus (COVID-19) within one minute. Their test uses ‘breath signatures’ to rapidly distinguish COVID-19 from other respiratory conditions such as asthma and influenza.
It identifies different chemical compounds or ‘biomarkers’ that become more abundant in the breath of people with COVID-19, but not people with these other respiratory conditions. Developed as part of a project called TOXI-Triage, the test is less invasive than the two leading tests for detecting COVID-19 – antigen detection and PCR – which involve swabs of bodily fluid.
The researchers said their method could improve the experience of taking a coronavirus test and ‘play a part in restarting the economy’. ‘Currently the two leading tests for COVID-19 – antigen detection and PCR – both utilise invasive means of taking samples,’ said Emma Brodrick at Cardiff-based diagnostics firm Imspex Group, which is collaborating on the research.
‘These can be uncomfortable for the patient and may discourage some from going to get a test they desperately need.’ Led by Loughborough University, the TOXI-Triage project was launched four years ago with the aim to determine the most effective ways to give medical and toxic assessments to the casualties of a chemical, biological, radioactive or nuclear event.
The team involved in the project repurposed some of the existing technology to design a COVID-19 breath test. As some of the main symptoms of COVID-19 are a continuous cough and breathing difficulties, it can be hard to identify whether people have the illness or are experiencing other respiratory conditions.
The team’s aim, therefore, was to identify the biomarkers present in the breath of someone affected by COVID-19 and distinguish those signatures from other respiratory tract infections. For trials of the technology, researchers recruited 98 patients in two locations – Edinburgh and Dortmund, Germany – of whom 31 were infected with coronavirus. The other patients had either asthma, chronic obstructive pulmonary disease, bacterial pneumonia or cardiac conditions.
From breath samples, the team identified significant increases in compounds in the breath of COVID-19 patients – aldehydes, including ethanal and octanal, as well as ketones (acetone and butanone). Exhaled concentrations of methanol, meanwhile, were lower in participants with COVID-19. The differences in all these chemical markers discriminated people with COVID-19 from the other respiratory conditions. Using breath tests, researchers differentiated patients with a COVID-19 diagnosis from a non-COVID-19 diagnosis with 80 per cent and 81.5 per cent accuracy in Edinburgh and Dortmund, respectively.
Scientists are hopeful the development and validation of their approach may allow rapid diagnosis of COVID-19 in the coming endemic flu seasons. Study author Paul Thomas at Loughborough University’s Department of Chemistry said the team is encouraged by the findings but added more data is required to develop the test.
‘If shown to be reliable, it offers the possibility for rapid identification or exclusion of COVID-19 in emergency departments or primary care that will protect healthcare staff, improve the management of patients and reduce the spread of COVID-19,’ he said. More data will help scientists continue to develop the test, while investor support will help scale manufacturing.
‘The Imspex Group is very pleased that our groundbreaking technology has delivered these exciting results,’ said Santi Dominguez, chief executive of the Imspex Group. ‘They offer the possibility not only to dramatically improve people’s experience of taking a Covid-19 test but also to play a part in restarting the economy through rapid screening of large numbers of people at airports and other transportation hubs, for example.’ The study has been published in The Lancet’s journal EclinicalMedicine.
Facts To Note:
PCR test: This COVID-19 test detects genetic material of the virus using a lab technique called polymerase chain reaction (PCR). Also called a molecular test, a health care worker collects fluid from a nasal or throat swab or from saliva.
Results may be available in minutes if analyzed onsite or a few days — or longer in locations with test processing delays — if sent to an outside lab. PCR tests are very accurate when properly performed by a health care professional, but the rapid test can miss some cases.
Antigen test: This test detects certain proteins in the virus. Using a nasal or throat swab to get a fluid sample, antigen tests can produce results in minutes. Because these tests are faster and less expensive than PCR tests, antigen tests may be more practical to use for large numbers of people.
A positive antigen test result is considered very accurate, but there’s an increased chance of false-negative results — meaning it’s possible to be infected with the virus but have a negative result. Depending on the situation, the doctor may recommend a PCR test to confirm a negative antigen test result.
Source: Mayo Clinic