Until now, the sensitivity of PCR tests to check for infection with the new coronavirus has been thought to be about 70%, but a research group led by Professor Takanori Toyoshima of the Graduate School of Medicine, Hokkaido University has published test results for about 2,000 cases. Upon examination, it was found that the test from saliva was 83-97%, and that from the nasopharyngeal swab was 77-93%, which was much higher.
According to Hokkaido University, Professor Toyoshima and his colleagues collected saliva and nasopharyngeal swabs from about 2,000 asymptomatic persons in an airport quarantine on international flights and a close contact test at a health center, and conducted a PCR test.
As a result, there were 48 positive cases of saliva and 46 cases of nasopharyngeal swab, and the sensitivity indicating the proportion of infected persons who were positively determined was higher than previously predicted.The specificity, which indicates the proportion of non-infected persons who were negatively determined, was 99.9% or more for both saliva and nasopharyngeal swab.
In order to prevent the outbreak of infection in the new corona, it is important to detect infected persons from asymptomatic persons such as close contacts and block the transmission of infection.However, the sensitivity of PCR tests to asymptomatic individuals was only said to be about 70% based on early small-scale surveys, and clear data were scarce.
Professor Toyoshima and his colleagues concluded from the results of this survey that PCR testing is a reliable method.In particular, the method in which the test subject collects saliva by himself / herself does not have the risk of infecting the sampler like nasopharyngeal swab, and the test subject's discomfort is small, so it is recommended as the standard method for the test. There is.
Paper information:[Clinical Infectious Diseases] Mass screening of asymptomatic persons for SARS-CoV-2 using saliva
