The role of saliva PCR assay in the diagnosis of COVID-19

Abstract

Introduction: The introduction of a self-collection sampling method with less discomfort would be of great benefit in reducing the risk of medical provider's contamination and patient's acceptance. The aim of the present study was to investigate saliva samples' diagnostic performance for the COVID-19 RT-PCR test compared to pharyngeal swabs.
 Methodology: From individuals referred to a medical center with presentations compatible with COVID-19 who were eligible for molecular diagnostic tests, 80 cases were selected. Nasopharyngeal and oropharyngeal swabs (placed into the same transport tube) along with self-collected saliva sample were taken from each participant for COVID-19 RT-PCR assay. The results of pharyngeal swabs and saliva sample were compared. 
 Results: Sixty-two (78%) infected cases were detected, of whom 31 (39%) cases tested positive for both pharyngeal swab and saliva samples. 24 (30%) and 7 (9%) cases tested positive only for pharyngeal or saliva samples, respectively. The overall percentage of agreement between pharyngeal swab and saliva sample was 61%, with a kappa value of 0.24 (p-value = 0.019, 95% CI: 0.04-0.44), showing a fair level of agreement. The diagnostic sensitivity of pharyngeal swabs was 88.71% (95% CI: 78.11-95.34), and the diagnostic sensitivity of saliva samples was 61.29% (95% CI: 48.07-73.40). Compared to pharyngeal swabs (oropharyngeal and nasopharyngeal swabs in the same collection tube), an important observation was that seven more positive cases were detected among saliva samples.
 Conclusions: The findings of the present study indicated that self-collected saliva samples cannot replace pharyngeal swabs. Still, saliva samples significantly increased the case detection rate and can be used along with pharyngeal swabs.

Comparison of Nasal Swabs, Nasopharyngeal Swabs, and Saliva Samples for the Detection of SARS-CoV-2 and other Respiratory Virus Infections

“…The strength of our study is that we compared viral concentrations in paired samples comprising two nasal swabs (particularly, using different number of rubs), two NPSs, and two saliva samples. Numerous studies have compared two sample types [ 11 – 14 , 20 , 21 ]; however, few studies have compared three or more sample types [ 9 , 10 , 22 ]. In particular, it is difficult to find studies comparing sample types for respiratory viruses and SARS-CoV-2.…”

Salivary SARS-CoV-2 RNA for diagnosis of COVID-19 patients: A systematic review and meta-analysis of diagnostic accuracy

“…All studies were published in 2020–2022 and were conducted in Argentina [31] , Belgium [32] , Bangladesh [33] , Brazil [14] , [34] , [35] , [36] , [37] , Canada [38] , [39] , [40] , [41] , [42] , Ethiopia [43] , France [44] , [45] , Greece [46] , India [47] , Iran [48] , Italy [49] , Japan [50] , [51] , [52] , [53] , Mexico [54] , [55] , Pakistan [56] , Philippines [57] , South Korea [58] , Thailand [59] , Turkey [60] , [61] , United Arab Emirates [62] , United Kingdom [63] , United States of America [64] , [65] , [66] , [67] , [68] , [69] , [70] , [71] , [72] , [73] . The total number of participants was 14,043, and the age varied between 18 and 106 years old.…”

“…The total number of participants was 14,043, and the age varied between 18 and 106 years old. Twenty-two studies only included patients who had symptoms of COVID-19 [14] , [31] , [33] , [34] , [37] , [43] , [47] , [48] , [50] , [51] , [53] , [54] , [55] , [57] , [59] , [60] , [61] , [65] , [68] , [70] , [71] , [73] , seventeen studies included symptomatic and asymptomatic patients [32] , [35] , [36] , [38] , [39] , [41] , [42] , [44] , [45] , [46] , [49] , [58] , [62] , [63] , [64] , [66] , [69] , one study included only asymptomatic patients [52] , and four studies did not report these data [40] , [56] , [67] , [72] . Other sources of information regarding demographics, characteristics of the population, and characteristics of the samples are available in Table 2 .…”

Rapid and Sensitive Assay of Helicobacter pylori With One-Tube RPA-CRISPR/Cas12 by Portable Array Detector for Visible Analysis of Thermostatic Nucleic Acid Amplification

“…It also requires large advanced equipment and professional personnel for operation, which is not suitable for large-scale on-site epidemiological screening ( Pohl et al, 2019 ; Gong and El-Omar, 2021 ), limiting the efficiency of detection. Currently, rapid and portable pathogen detection methods based on CRISPR nucleic acid detection systems have been developed and used widely, especially in COVID-19, with satisfied diagnostic performance for both saliva samples and pharyngeal swab samples ( Abdollahi et al, 2022 ). In this study, we detected H. pylori in mimicked saliva samples based on the one-tube RPA-CRISPR platform.…”