End of nose swabs? New study suggests mouthwash test is just as accurate as nasal exam in detecting Covid

People may soon be able to use mouthwash to test whether they have Covid instead of the invasive nasal and throat swabs.

Scientists have found that a 'gargle lavage' mouthwash test is just as accurate at the nasopharyngeal swabs currently used to detect if a person has Covid and is also a much simpler process.

The test involves the patient gargling a solution as you would with mouthwash and then spitting it out into a cup where it can be analysed. 

The study, carried out by the University of Konstanz, in Germany, involved 80 participants of whom 26 tested positive for Covid when tested with a swab.

Scientists at German university found a mouthwash test, which involves gargling a solution before spitting it out into a cup to be tested, is as reliable as a nasal swab (stock picture)

Gargle lavage: How does the mouthwash test for Covid work? 

Mouthwash tests, also known as a gargle lavage, involve swilling a solution round the mouth before submitting it as a sample.

Patients must pour the solution into their mouth, swill it round their mouth and then gargle with the solution.

This pattern must be repeated three times before the solution is then spat back into a sample tube for testing.

The whole sample process should take no more than 30 seconds. 

Researchers found that the same 26 participants were found to be positive when they were tested using the mouthwash.

Scientists believe the mouthwash, which uses a polymerase chain reaction to detect the virus, provides real-time results and can be administered by anyone.

Corresponding author and professor of cell biology Christof R. Hauck, PhD, said: 'Our results show that in all cases, where people were positively tested by the gold standard nasal swabbing, one could also detect the virus in gargle lavage by the same RT-PCR method.'

Dr Huack said the test could be carried out by anyone, including non-medical professionals, unlike the nasopharyngeal swab tests.

He added: 'We usually sent the patients with the gargle solution and sampling container outside.

'There, they gargled in front of a window, observed by a physician’s staff member. Thus, we need not expose trained personnel to the danger of taking samples from so many potentially infected people.'

Researchers say the mouthwash test will be more widely accepted than the more invasive nasopharyngeal test which is uncomfortable for patients and must be carried out by a medic

The study involved testing patients with known respiratory symptoms or patients who had come into contact with those already infected with the virus.

Each patient underwent a swab test first and then self-tested using the gargle lavage.

Dr Huack added: 'Besides performing diagnostics on symptomatic patients, we are involved in regular SARS-CoV-2 surveillance on our university campus, where we test people twice a week.

'As nasal swabbing is not very pleasant, we were looking for an alternative, and gargle lavage turned out to be highly accepted.

'The fact that both tests came to the exact same results leads the research team to conclude that the painless self-collection of gargle lavage provides a suitable and uncomplicated source for reliable SARS-CoV-2 detection.'

The findings will appear in the journal Microbiology Spectrum.