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Observational Study
. 2022 Jan 7:2022:6478434.
doi: 10.1155/2022/6478434. eCollection 2022.

Validation of a Saliva-Based Test for the Molecular Diagnosis of SARS-CoV-2 Infection

Michela Bulfoni  1   2 , Emanuela Sozio  3 , Barbara Marcon  4 , Maria De Martino  1 , Daniela Cesselli  1   2 , Chiara De Carlo  3 , Romina Martinella  4 , Angelica Migotti  4 , Eleonora Vania  3 , Agnese Zanus-Fortes  3 , Jessica De Piero  3 , Emanuele Nencioni  5 , Carlo Tascini  1   3 , Miriam Isola  1 , Francesco Curcio  1   4
Affiliations
Observational Study

Validation of a Saliva-Based Test for the Molecular Diagnosis of SARS-CoV-2 Infection

Michela Bulfoni et al. Dis Markers. .

Abstract

Background: Since the beginning of the pandemic, clinicians and researchers have been searching for alternative tests to improve the screening and diagnosis of the SARS-CoV-2 infection. Currently, the gold standard for virus identification is the nasopharyngeal (NP) swab. Saliva samples, however, offer clear, practical, and logistical advantages but due to a lack of collection, transport, and storage solutions, high-throughput saliva-based laboratory tests are difficult to scale up as a screening or diagnostic tool. With this study, we aimed to validate an intralaboratory molecular detection method for SARS-CoV-2 on saliva samples collected in a new storage saline solution, comparing the results to NP swabs to determine the difference in sensitivity between the two tests.

Methods: In this study, 156 patients (cases) and 1005 asymptomatic subjects (controls) were enrolled and tested simultaneously for the detection of the SARS-CoV-2 viral genome by RT-PCR on both NP swab and saliva samples. Saliva samples were collected in a preservative and inhibiting saline solution (Biofarma Srl). Internal method validation was performed to standardize the entire workflow for saliva samples.

Results: The identification of SARS-CoV-2 conducted on saliva samples showed a clinical sensitivity of 95.1% and specificity of 97.8% compared to NP swabs. The positive predictive value (PPV) was 81% while the negative predictive value (NPV) was 99.5%. Test concordance was 97.6% (Cohen's Kappa = 0.86; 95% CI 0.81-0.91). The LoD of the test was 5 viral copies for both samples.

Conclusions: RT-PCR assays conducted on a stored saliva sample achieved similar performance to those on NP swabs, and this may provide a very effective tool for population screening and diagnosis. Collection of saliva in a stabilizing solution makes the test more convenient and widely available; furthermore, the denaturing properties of the solution reduce the infective risks belonging to sample manipulation.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1
Figure 1
Ct values for paired samples in the 156 patients tested for SARS-CoV-2 infection.
Figure 2
Figure 2
Bland-Altman (B&A) plot showing concordance between Ct values available for the 71 paired tests.
Figure 3
Figure 3
Comparison between Ct values reached from fresh and stabilized saliva samples collected from the same patients.
See this image and copyright information in PMC

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References

    1. CDC. Coronavirus Disease 2019 (COVID-19) USA: Centers for Disease Control and Prevention; 2020.
    1. Bhattacharya A. K., Maiti A. Coronavirus disease-2019: an overview and update. Bengal Physician Journal . 2019;6:45–47.
    1. Uddin M., Mustafa F., Rizvi T. A., et al. SARS-CoV-2/COVID-19: viral genomics, epidemiology, vaccines, and therapeutic interventions. Viruses . 2020;12(5):p. 526. doi: 10.3390/v12050526. - DOI - PMC - PubMed
    1. Commissioner O of the. Which Uses a New Method of Saliva Sample Processing . FDA; 2020. Coronavirus (COVID-19) Update: FDA Issues Emergency Use Authorization to Yale School of Public Health for SalivaDirect.
    1. Wang W., Xu Y., Gao R., et al. Detection of SARS-CoV-2 in different types of clinical specimens. JAMA . 2020;323(18):1843–1844. doi: 10.1001/jama.2020.3786. - DOI - PMC - PubMed

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