Saliva for diagnosis of SARS‐CoV‐2: First report from India

Abstract

There are very few studies in search of an alternate and convenient diagnostic tool which can substitute nasopharyngeal swab (NPS) specimen for detection of SARS‐CoV‐2. In the study we analyzed, the comparison and agreement between the feasibility of using the saliva in comparison to NPS for diagnosis of SARS‐CoV‐2. A total number of 74 patients were enrolled for this study. We analyzed and compared the NPS and saliva specimen collected within 48 h after the symptom onset. We carried out real‐time quantitative polymerase chain reaction, gene sequencing for the detection and determination SARS‐CoV‐2 specific genes. Phylogenetic tree was constructed to establish the isolation of viral RNA from saliva. We used the Bland–Altman model to identify the agreement between two specimens. This study showed a lower cycle threshold (CT) mean value for the detection of SARS‐CoV‐2 ORF1 gene (mean, 27.07; 95% confidence interval [CI], 25.62 to 28.52) in saliva methods than that of NPS (mean 28.24; 95% CI, 26.62 to 29.85) specimen although the difference is statistically nonsignificant (p > .05). Bland–Altman analysis produced relatively smaller bias and high agreement between these two clinical specimens. Phylogenetic analysis with the RdRp and S gene confirmed the presence of SARS‐CoV‐2 in the saliva samples. Saliva represented a promising tool in COVID‐19 diagnosis and the collection method would reduce the exposure risk of frontline health workers which is one of the major concerns in primary healthcare settings.

ESCMID COVID-19 guidelines: diagnostic testing for SARS-CoV-2

“… In children <12 years old with signs and symptoms compatible with COVID-19, we suggest the use of NAAT in nasopharyngeal swab samples versus NAAT in saliva samples for diagnosis of COVID-19. Weak against Very low [ 90 , 94 , 95 , 99 , 103 , 107 , 108 , 114 , 115 , 117 ] 25 In patients ≥12 years old with signs and symptoms compatible with COVID-19, should saliva sampling be used, compared with nasopharyngeal swab sampling for diagnosis of COVID-19 with NAAT? In patients ≥12 years old with signs and symptoms compatible with COVID-19, we suggest the use of NAAT in nasopharyngeal swab samples versus NAAT in saliva samples for diagnosis of COVID-19.…”

“… In patients with signs and symptoms compatible with COVID-19 at risk for severe illness, we suggest the use of NAAT in nasopharyngeal swab samples versus NAAT in saliva samples for diagnosis of COVID-19. Weak against Very low [ 13 , [90] , [91] , [92] , [93] , [94] , [95] , [96] , [97] , [98] , [99] , [100] , [101] , [102] , [103] , [104] , [105] , [106] , [107] , [108] , [109] , [110] , [111] , [112] , [113] , [114] , [115] , [116] , [117] , [118] ] a Strength of recommendation (strong against, weak against, in research only, weak for, strong for). b Overall certainty of the evidence (high, moderate, low, very low).…”

A Large Cohort Study of SARS-CoV-2 Detection in Saliva: A Non-Invasive Alternative Diagnostic Test for Patients with Bleeding Disorders

“…Although our results showed that, in general, saliva is less sensitive when compared to NPS and OPS, the collection of these two respiratory specimens are not an easy or an ideal method for widespread screening and may be associated with various degrees of discomfort for the patient [31]. This can be more dangerous for patients having thrombocytopenia or any other coagulation disorder [32], in which the sample collection can cause bleeding.…”

Validating saliva as a biological sample for cost-effective, rapid and routine screening for SARS-CoV-2

“…Evidence related to using saliva for SARS-CoV-2 testing is evolving, and recent studies have reported promising results [4, 5]. Unfortunately, saliva-based tests in India are explored by very few studies [5, 6].…”