RCSI finds saliva test for Covid almost as accurate as throat and nose swab

8 Sep 2021

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The saliva test could offer a less intrusive form of screening for Covid-19.

Testing for Covid-19 could become much simpler, as research from the Royal College of Surgeons in Ireland (RCSI) found that a PCR test using saliva is almost as accurate as the standard nose and throat swab.

The research focused on the SalivaDirect sampling method, which was developed by the Yale School of Public Health and authorised for emergency use by the US Food and Drug Administration. The RCSI study was published in HRB Open Research.

Researchers collected samples through the standard nasal and throat swab method, as well as saliva samples from more than 300 symptomatic and asymptomatic participants. This ranged from asymptomatic RCSI students to patients who had been admitted to Beaumont Hospital with respiratory symptoms.

They found that 94pc of the positive nose and throat swabs also tested positive with the saliva test. Among the negative nose and throat samples, 96pc also showed a negative result with the saliva test.

These results were consistent with the original SalivaDirect trial, suggesting that detecting Covid-19 from saliva could provide an accurate but less intrusive alternative to nose and throat swabs.

“Our study has further validated that saliva testing can offer an accurate alternative to the more invasive commonly used nose and throat swabbing method,” said Prof Steve Kerrigan, the joint lead author of the study and deputy head of RCSI School of Pharmacy and Biomolecular Sciences.

“The saliva sample to test for Covid-19 can be easily collected by the person themselves so has the potential to increase compliance with screening, particularly those who require frequent repeated testing. As the saliva test does not require a healthcare professional to conduct it, this method also reduces the risk of infection for test centre staff associated with conducting the nasal and throat swabbing.”

Last month, other researchers at RCSI released new findings around ‘long Covid’, while previous research examined the link between blood clotting and the severity of infection.

Sam Cox is a journalist at Silicon Republic covering sci-tech news

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