Self-collected unstimulated saliva, oral swab, and nasopharyngeal swab specimens in the detection of SARS-CoV-2

Objectives The presence of SARS-CoV-2 virus in the saliva of patients infected with COVID-19 has been confirmed by several studies. However, the use of saliva for the diagnosis of COVID-19 remains limited, because of the discrepancies in the results, which might be due to using different saliva sampling methods. The purpose of this study was to compare the consistency of SARS-CoV-2 detection using two different saliva sampling methods (oral swab and unstimulated saliva) to that of the standard nasopharyngeal swab. Methods Fifty-five subjects were recruited from a pool of COVID-19 inpatient at the Hospital Israelita Albert Einstein (HIAE), Brazil. Nasopharyngeal swab, oral swab, and self-collected unstimulated saliva samples were examined for SARS-CoV-2 using RT-PCR. Results Self-collected unstimulated saliva demonstrated 87.3% agreement in the detection of SARS-CoV-2 virus as compared with the nasopharyngeal swab, while oral swab displayed 65.9% agreement when compared to nasopharyngeal swab and 73% when compared to self-collected unstimulated saliva. Conclusion Unstimulated self-collected saliva samples have shown a higher agreement with the nasopharyngeal swab samples for SARS-COV-2 detection than that obtained when using oral swab samples.

Automated summary

The study found that self-collected unstimulated saliva samples have a higher agreement (87.3%) with nasopharyngeal swab samples in detecting the SARS-CoV-2 virus compared to oral swab samples (65.9% agreement with nasopharyngeal swab and 73% with self-collected unstimulated saliva).