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Research article
Comparison of Saliva with Healthcare Workers- and Patient-Collected Swabs in the Diagnosis of COVID-19 in a Large Cohort
Mitnala Sasikala
Asian Institute of Gastroenterology
Corresponding Author
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Background: A considerable amount of evidence demonstrates the potential of saliva in the diagnosis of COVID-19. Our aim was to determine the sensitivity of saliva versus swabs collected by healthcare workers (HCWs) and patients themselves to assess whether saliva detection can be offered as a cost-effective, risk-free method of SARS-CoV-2 detection.
Methods: This study was conducted in a hospital involving outpatients and hospitalized patients. A total of 3018 outpatients (asymptomatic: 2683, symptomatic: 335) were screened. Of these, 200 qRT-PCR-confirmed SARS-CoV-2-positive patients were recruited (81 asymptomatic, 119 symptomatic). In addition, 101 SARS-CoV-2-positive hospitalized patients with symptoms were also enrolled in the study. From outpatients, HCWs collected nasopharyngeal swabs (NPS), saliva were obtained. From inpatients, HCWs collected swabs, patient-collected swabs, and saliva were obtained. qRT-PCR was performed to detect SARS-CoV-2 by TAQPATH assay to determine the sensitivity of saliva detection. Sensitivity, specificity and positive/negative predictive values (PPV, NPV) of detecting SARS-CoV-2 were calculated using MedCalc.
Results: Of 3018 outpatient swabs tested by qRT-PCR, 200 were positive (males: 140, females: 60; aged 37.85±12.76 years). Of these, saliva was positive in 128 (64%); 39 of 81 asymptomatic (47%),89 of 119 symptomatic patients (74.78%). Sensitivity of detection was 60.9% (55.4-66.3%, CI 95%), with a negative predictive value of 36%(32.9-39.2%, CI 95%).Among 101 hospitalized patients (males:65, females: 36; aged 53.43±15.58 years), with HCW collected NPS as comparator, sensitivity of saliva was 56.1% (47.5-64.5, CI 95%), specificity 63.5%(50.4-75.3, CI95%) with PPV of 77.2% and NPV of 39.6% and that of self-swab was 52.3%(44-60.5%, CI95%), specificity 56.6% (42.3-70.2%, CI95%) with PPV 77.2% and NPV29.7%. Comparison of positivity with the onset of symptoms revealed highest detection in saliva on day 3 after onset of symptoms. Additionally, only saliva was positive in 13 (12.8%) hospitalized patients.
Conclusion: Our results demonstrate the use of saliva to detect SARS-COV-2 in symptomatic patients early after the onset of symptoms. Additionally, these results suggest that saliva may not be recommended as a screening tool at the community level due to the lower detection rate than that for swabs. Saliva testing in symptomatic patients whose nasopharyngeal swab does not detect SARS-CoV-2 reduces false negativity.
Keywords
SARS-COV-2, Saliva, Healthcare worker, Nasopharyngeal swab
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CURRENT STATUS: Under Review
Version 1
Posted 22 Dec, 2020
No community comments so far
Editorial decision: Major revision
On 19 Jan, 2021
Review #2 received
Received 17 Jan, 2021
Reviewer #2 agreed
On 29 Dec, 2020
Reviewers invited
Invitations sent on 27 Dec, 2020
Reviewer #1 agreed
On 27 Dec, 2020
Review #1 received
Received 27 Dec, 2020
Editor assigned
On 26 Dec, 2020
Submission checks complete
On 19 Dec, 2020
Editor invited
On 16 Dec, 2020
First submitted
On 16 Nov, 2020
Metrics
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PDF Downloads: ...
HTML Views: ...
Subject Areas
Infectious Diseases
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This preprint is under consideration at BMC Infectious Diseases. A preprint is a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research article
Comparison of Saliva with Healthcare Workers- and Patient-Collected Swabs in the Diagnosis of COVID-19 in a Large Cohort
Mitnala Sasikala
Asian Institute of Gastroenterology
Corresponding Author
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Under Review
Version 1
Posted 22 Dec, 2020
No community comments so far
Editorial decision: Major revision
On 19 Jan, 2021
Review #2 received
Received 17 Jan, 2021
Reviewer #2 agreed
On 29 Dec, 2020
Reviewers invited
Invitations sent on 27 Dec, 2020
Reviewer #1 agreed
On 27 Dec, 2020
Review #1 received
Received 27 Dec, 2020
Editor assigned
On 26 Dec, 2020
Submission checks complete
On 19 Dec, 2020
Editor invited
On 16 Dec, 2020
First submitted
On 16 Nov, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Infectious Diseases
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: A considerable amount of evidence demonstrates the potential of saliva in the diagnosis of COVID-19. Our aim was to determine the sensitivity of saliva versus swabs collected by healthcare workers (HCWs) and patients themselves to assess whether saliva detection can be offered as a cost-effective, risk-free method of SARS-CoV-2 detection.
Methods: This study was conducted in a hospital involving outpatients and hospitalized patients. A total of 3018 outpatients (asymptomatic: 2683, symptomatic: 335) were screened. Of these, 200 qRT-PCR-confirmed SARS-CoV-2-positive patients were recruited (81 asymptomatic, 119 symptomatic). In addition, 101 SARS-CoV-2-positive hospitalized patients with symptoms were also enrolled in the study. From outpatients, HCWs collected nasopharyngeal swabs (NPS), saliva were obtained. From inpatients, HCWs collected swabs, patient-collected swabs, and saliva were obtained. qRT-PCR was performed to detect SARS-CoV-2 by TAQPATH assay to determine the sensitivity of saliva detection. Sensitivity, specificity and positive/negative predictive values (PPV, NPV) of detecting SARS-CoV-2 were calculated using MedCalc.
Results: Of 3018 outpatient swabs tested by qRT-PCR, 200 were positive (males: 140, females: 60; aged 37.85±12.76 years). Of these, saliva was positive in 128 (64%); 39 of 81 asymptomatic (47%),89 of 119 symptomatic patients (74.78%). Sensitivity of detection was 60.9% (55.4-66.3%, CI 95%), with a negative predictive value of 36%(32.9-39.2%, CI 95%).Among 101 hospitalized patients (males:65, females: 36; aged 53.43±15.58 years), with HCW collected NPS as comparator, sensitivity of saliva was 56.1% (47.5-64.5, CI 95%), specificity 63.5%(50.4-75.3, CI95%) with PPV of 77.2% and NPV of 39.6% and that of self-swab was 52.3%(44-60.5%, CI95%), specificity 56.6% (42.3-70.2%, CI95%) with PPV 77.2% and NPV29.7%. Comparison of positivity with the onset of symptoms revealed highest detection in saliva on day 3 after onset of symptoms. Additionally, only saliva was positive in 13 (12.8%) hospitalized patients.
Conclusion: Our results demonstrate the use of saliva to detect SARS-COV-2 in symptomatic patients early after the onset of symptoms. Additionally, these results suggest that saliva may not be recommended as a screening tool at the community level due to the lower detection rate than that for swabs. Saliva testing in symptomatic patients whose nasopharyngeal swab does not detect SARS-CoV-2 reduces false negativity.
Figure 1
Figure 2
Figure 3
Figure 4