Japanese Society for Infection Prevention and Control-Online Journal

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Article in Japanese

Diagnostic Accuracy of SARS-CoV-2 Infection According to Sampling of Specimen for PCR-More Useful PCR Sampling from Oral Cavity-

Ritsuo TAKAGI¹⁾, Yoshinari TANABE²⁾, Kouji SUDO³⁾, Eiko YAMADA¹⁾ and Shingo KATO³⁾⁴⁾
¹⁾Division of Oral and Maxillofacial Surgery, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, ²⁾Department of Internal Medicine, Niigata Prefectural Shibata Hospital, ³⁾Hanah MediTech Co. Ltd., ⁴⁾Department of Microbiology, Keio University School of Medicine

Although nasopharyngeal swab is widely used, the use of saliva for the detection of SARS-CoV-2 is also accepted. However, the method of saliva collection has not yet been well investigated. Thus, to make the assay using saliva more reliable, we compared the positivity rates and viral loads in three paired samples of nasopharyngeal and tongue swabs and saliva retained in the floor of the mouth, which were simultaneously obtained from 21 patients with SARS-CoV-2. Viral RNA was detected in 95.2% (20/21) of nasopharyngeal swab, 85.7% (18/21) of tongue swab, and 52.4% (11/21) of retained saliva samples. The viral loads were in the following order: nasopharyngeal swab > tongue swab > retained saliva samples. Our results indicated that a tongue swab is usable and provides more sensitivity for SARS-CoV-2 detection than natural saliva. However, it is important to consider the possibility of a false negative and that re-examination would be required if the result is negative but a SARS-CoV-2 infection is highly suspected.

Key words：COVID-19, nasopharyngeal swab, tongue swab, retained saliva, viral load

e-mail: takagi＠dent.niigata-u.ac.jp

Received: October 1, 2021
Accepted: April 6, 2022

37 (4)：139─142,2022