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. 2020 Oct 1:13:3393-3399.
doi: 10.2147/IDR.S275152. eCollection 2020.

Saliva as an Alternative Specimen for Molecular COVID-19 Testing in Community Settings and Population-Based Screening

Abiola Senok #  1 , Hanan Alsuwaidi #  1 , Yusrah Atrah  2 , Ola Al Ayedi  3 , Janan Al Zahid  2 , Aaron Han  1 , Asma Al Marzooqi  3 , Saba Al Heialy  1   4 , Basel Altrabulsi  5 , Laila AbdelWareth  5   6 , Youssef Idaghdour  7 , Raghib Ali  7 , Tom Loney  1 , Alawi Alsheikh-Ali  1
Affiliations

Saliva as an Alternative Specimen for Molecular COVID-19 Testing in Community Settings and Population-Based Screening

Abiola Senok et al. Infect Drug Resist. .

Abstract

Purpose: With the easing of restriction measures, repeated community-based sampling for tracking new COVID-19 infections is anticipated for the next 6 to 12 months. A non-invasive, self-collected specimen like saliva will be useful for such public health surveillance. Investigations on the use of saliva for SARS-CoV-2 RT-PCR have largely been among COVID-19 in-pa\tients and symptomatic ambulatory patients with limited work in a community-based screening setting. This study was carried out to address this paucity of data and reported discrepancies in diagnostic accuracy for saliva samples.

Patients and methods: From 29th June to 14th July 2020, adults presenting for COVID-19 testing at a community-based screening facility in Dubai, United Arab Emirates were recruited. Clinical data, nasopharyngeal swab in universal transport media and drooling saliva in sterile containers were obtained. Reverse transcriptase PCR amplification of SARS-CoV-2 RdRp and N genes was used to detect the presence of the SARS-CoV-2 virus.

Results: Of the 401 participants, 35 (8.7%) had viral detection in at least one specimen type and the majority (n=20/35; 57.1%) were asymptomatic. Both swab and saliva were positive in 19 (54.2%) patients, while 7 (20.0%) patients had swab positive/saliva negative results. There were 9 (25.7%) patients with saliva positive/swab negative result and this included 5 asymptomatic COVID-19 patients undergoing repeat screening. Using the swab as the reference gold standard, the sensitivity and specificity of saliva were 73.1% (95% CI 52.2-88.4%) and 97.6% (95% CI 95.5-98.9%) while the positive and negative predictive values were 67.9% (95% CI 51.5-80.8%) and 98.1% (95% CI 96.5-99.0%), respectively.

Conclusion: The findings suggest good diagnostic accuracy for saliva and feasibility of utilization of specimen without transport media for SARS-CoV-2 RT-PCR. Saliva represents a potential specimen of choice in community settings and population-based screening.

Keywords: SARS-CoV-2; molecular test; nasopharyngeal swab; population-based screening; saliva.

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Conflict of interest statement

YA, JAZ are employees of Unilabs UAE but this did not influence the study design, and they have no competing interests to declare. None of the other authors has any financial or other relationships that may constitute a conflict of interest.

Figures

Figure 1
Figure 1
SARS-CoV-2 RT-PCR cycle threshold (Ct) values for the target genes in patients with paired positive samples (i.e. both swab and saliva samples positive).
Figure 2
Figure 2
Comparison of RT-PCR cycle threshold (Ct) in paired positive swab and saliva versus samples with only one specimen type positive.
See this image and copyright information in PMC

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