Saliva and deep throat sputum swabs are promising diagnostic tools for first-line screening of COVID-19 infection

Objectives:
What are the reliability and sensitivity of SARS-CoV-2 (COVID-19) detection in saliva and deep throat sputum (DTS) compared to nasopharyngeal, combined naso/oropharyngeal and oropharyngeal swabs?

Study design:
This review article included 26 studies.

Results and conclusions:   
The investigators found an overall sensitivity of 97% [95% CI = 86 to 100] for bronchoalveolar lavage fluid, 92% [95% CI = 80 to 99] for double naso/oropharyngeal swabs, 87% [95% CI = 77 to 95] for nasopharyngeal swabs, 83% [95% CI = 77 to 89] for saliva, 82% [95% CI = 76 to 88] for deep throat sputum and 44% [95% CI = 35 to 52] for oropharyngeal swabs among symptomatic patients, respectively.

The investigators found regardless of the type of specimens, the viral load and sensitivity in the severe patients were higher than mild and in the symptomatic patients higher than asymptomatic cases.

The investigators concluded the present review provides evidence for the diagnostic value of different respiratory specimens and supports saliva and deep throat sputum (DTS) as promising diagnostic tools for first-line screening of SARS-CoV-2 (COVID-19) infection based on RT-PCR assay. However, sampling, storing and laboratory assay needs to be optimized and validated before introducing a definite diagnosis tool.
Saliva, deep throat sputum, nasopharyngeal and even double naso/oropharyngeal swabs showed approximately similar results and sensitivity was directly related to the disease severity. This review article revealed a relationship between viral load, disease severity and test sensitivity. None of the specimens showed appropriate diagnostic sensitivity for asymptomatic patients.

Original title:
Are saliva and deep throat sputum as reliable as common respiratory specimens for SARS-CoV-2 detection? A systematic review and meta-analysis by Khiabani K and Amirzade-Iranaq MH.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7987587/

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