Saliva test a 'valid and accurate' alternative to nose/throat PCR swab, RCSI study finds

The less invasive alternative to the nasal and throat swab could allow for greater capacity and frequency of testing for people who require regular screening.

Using saliva to test for Covid-19 has been found to be almost as accurate as the current PCR test of a nose and throat swab.

That is according to the RCSI University of Medicine and Health Sciences, which suggest that the less invasive alternative to the nasal and throat swab could allow for greater capacity and frequency of testing for people who require regular screening.

The study, which has been approved by an international panel of peer-reviewers, tested the "gold standard" nasal and throat swabbing and the recently developed SalivaDirect method and involved the collection of samples from more than 300 symptomatic and asymptomatic people.

The results revealed that 94% of the positive nose and throat swabs also tested positive on the saliva test, while 96% of negative samples also tested negative on the saliva test.

The results indicate that the use of saliva to test for Covid-19 "represents a valid and accurate and less invasive alternative" to the standard nasal and throat PCR test.

“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 Professor Steve Kerrigan, 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 / throat swabbing.” 

RCSI University of Medicine and Health Sciences carried out the study as part of a collaboration with University College Dublin (UCD) and Beaumont Hospital in Dublin.

SalivaDirect was developed by the Yale School of Public Health and has been authorised for emergency use by the Food and Drug Administration (FDA).