Validation of a Saliva-Based Test for the Molecular Diagnosis of SARS-CoV-2 Infection
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- Evaluated articles (Rapid Reviews Infectious Diseases)
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.
Article activity feed
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Diana Rose Ranoa
Review 2: "Validation of a Saliva-Based Test for the Molecular Diagnosis of SARS-CoV-2 Infection"
This study finds that saliva samples can be used for population screening at a high rate of sensitivity and specificity, supporting other studies already showing that saliva tests can be comparable to NP swabs for COVID-19 testing. While reliable, there are some study flaws.
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Jianhui Wang
Review 1: "Validation of a Saliva-Based Test for the Molecular Diagnosis of SARS-CoV-2 Infection"
This study finds that saliva samples can be used for population screening at a high rate of sensitivity and specificity, supporting other studies already showing that saliva tests can be comparable to NP swabs for COVID-19 testing. While reliable, there are some study flaws.
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Jianhui Wang, Diana Rose Ranoa
Reviews of: "Validation of a Saliva-Based Test for the Molecular Diagnosis of SARS-CoV-2 Infection"
Reviewers: J Wang (US) | 📗📗📗📗◻️ • D Ranoa (University of Illinois) | 📒📒📒◻️◻️
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SciScore for 10.1101/2021.09.10.21263072: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: All samples collected were anonymized using an alpha-numeric identification code, and the study was approved by the Local Ethics Committee.
Field Sample Permit: The conserving solution contained in the saliva collection tubes was provided by Biofarma Srl and it is protected by intellectual property.Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Table 2: Resources
Software and Algorithms Sentences Resources All analyses were performed by STATA 16 statistical software and statistical significance was set at p < 0.05. STATAsuggested: (Stata, RRID:SCR_012763)Results from OddPub: We did not detect open data. We also did not …
SciScore for 10.1101/2021.09.10.21263072: (What is this?)
Please note, not all rigor criteria are appropriate for all manuscripts.
Table 1: Rigor
Ethics IRB: All samples collected were anonymized using an alpha-numeric identification code, and the study was approved by the Local Ethics Committee.
Field Sample Permit: The conserving solution contained in the saliva collection tubes was provided by Biofarma Srl and it is protected by intellectual property.Sex as a biological variable not detected. Randomization not detected. Blinding not detected. Power Analysis not detected. Table 2: Resources
Software and Algorithms Sentences Resources All analyses were performed by STATA 16 statistical software and statistical significance was set at p < 0.05. STATAsuggested: (Stata, RRID:SCR_012763)Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).
Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:Saliva samples can sometimes be difficult to handle with existing RNA extraction methods and equipment and the heterogeneity of saliva specimen can represent limitations, but there are several advantages (14, 31, 32, 36). Actually, saliva sample collection is non-invasive and can be easily performed by the individual themselves and this could reduce the risk of transmission to the sample takers (13, 14, 17). In our study, a high-concentrate saline solution was employed to collect saliva samples. The ionic strength of the solution acts as denaturing agent and destroys all protein and muco-protein’s structure, interfering on the interaction between the virus and the host cell. This observation represents an additional key aspect in mitigate the risk of infection during sample collection and allows to bypass the absence of dedicate spaces for the safe conduction of laboratory activity. In this work, the combination of the saliva self-collection procedure with the inhibiting property of Bsawb solution, could be considered an advancement to facilitate COVID-19 diagnostics. Furthermore, saliva collection facilitates sampling of children or disabled and this can increase the acceptance to routine testing practices performed at repeated intervals among high-risk populations. This modality of sample collection is easy and non-invasive, so it may be performed by non-healthcare professionals or individuals themselves who are properly instructed (13, 14, 16, 35). Overall, recent studies ...
Results from TrialIdentifier: No clinical trial numbers were referenced.
Results from Barzooka: We did not find any issues relating to the usage of bar graphs.
Results from JetFighter: We did not find any issues relating to colormaps.
Results from rtransparent:- Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
- Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
- No protocol registration statement was detected.
Results from scite Reference Check: We found no unreliable references.
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