This new test can detect Covid in saliva accurately

Tokyo Scientists have shown that an antigen-based test for quantifying SARS-CoV-2, the virus behind Covid-19, in saliva samples is simple, accurate, rapid, and more conducive for mass-screening.

A team of scientists from Hokkaido University in Japan used a novel antigen-based kit, Lumipulse SARS-CoV-2 Ag kit (Lumipulse), developed by a Japanese company Fujirebio in June 2020 to assess the efficiency and accuracy of the test compared to RT-PCR. Their findings show that the antigen detection kit, which is used to perform chemiluminescent enzyme immunoassay (CLEIA), can detect SARS-CoV-2 within 35 minutes and with good accuracy. The study was published in the journal The Lancet Microbe.

The scientists tested 2,056 individuals from three cohorts: patients with clinically confirmed Covid-19, individuals who had contacted patients with Covid-19, and individuals tested on arrival at Tokyo and Kansai International Airports. The benefit of using saliva samples is the ease of collection: it is quick and can be collected by the individuals being tested, reducing the risk that healthcare workers are exposed to the virus.

Furthermore, self-collection of saliva allows multiple samples to be collected simultaneously for expeditious screening of visitors at large gatherings. More than a year into the Covid-19 pandemic, the RT-PCR test remains the gold standard for detection of the SARS-CoV-2 virus. This method requires trained personnel at every step, from collection of nasopharyngeal swab (NPS) samples to interpretation of the results; in addition, the entire process ranges from 24-48 hours on average.

As the virus can be transmitted by an infected person before symptoms develop, and is even transmitted by individuals who are asymptomatic, the ability to screen a large number of people quickly is vital to controlling and preventing the spread of the pandemic.