Objectives The optimal diagnostic specimen to detect SARS-CoV-2 by PCR in the upper respiratory tract is unclear. Mouthwash fluid has been reported as an alternative to nasopharyngeal and oropharyngeal swabs. We compared mouthwash fluid with a combined oro-nasopharyngeal swab regarding test performance. Methods In a large refugee facility, we retested individuals with a previous positive test for SARS-CoV-2 and their quarantined close contacts. All individuals were asymptomatic at the time of testing. First, a mouthwash (gargling for at least 5 s) with sterile water was performed. Then, with a single flocked swab the back of the throat and subsequently the nasopharynx were sampled. Samples were inactivated and analysed on a Roche cobas 6800 ® system with the Roche SARS-CoV-2 test. Results Of 76 individuals, 39 (51%) tested positive for SARS-CoV-2 by oro-nasopharyngeal swab. Mouthwash detected 13 of 76 (17%) infections, but did not detect any additional infection. Samples that were positive in both tests, had lower cycle threshold ( Ct )-values for oro-nasopharyngeal samples, indicating a higher virus concentration, compared to samples only positive in oro-nasopharyngeal swabs. Conclusion Mouthwash is not as sensitive as combined oro-nasopharyngeal swab in detecting upper respiratory tract infection.
【저자키워드】 COVID19, sensitivity, specificity, Diagnostic accuracy, SARS2, Mouthwash, Oronasopharyngeal swab, 【초록키워드】 SARS-CoV-2, Infection, upper respiratory tract infection, diagnostic, respiratory tract infection, virus, infections, PCR, Asymptomatic, cycle threshold, nasopharyngeal, swabs, nasopharynx, Swab, Mouthwash, respiratory, Roche, upper respiratory tract, inactivated, Concentration, water, alternative, oropharyngeal swabs, individual, specimen, Positive test, positive, SARS-CoV-2 test, sterile water, back, objective, Result, tested, detect, Sample, reported, was performed, analysed, individuals, 【제목키워드】 SARS-CoV-2, Swab, PCR assay,