Review of using saliva for COVID-19 testing

Abstract

Saliva is a hypotonic solution of gingival, salivary acini, and exudate sulcus fluid from the oral mucosa. Saliva contains proteins, DNA, RNA, micro-RNA, and metabolites; hence, it can be detected early in viruses, bacteria, as well as systemic diseases. It has been reported to show an ideal role in the isolation of proteins, peptides, and batches of viruses by molecular assays. Previously, saliva has been used as a biomarker to help detect oral cancer, caries, periodontal disease, diabetes, breast cancer, and lung cancer. Investigate research on saliva development as well as the utilized laboratory techniques serving as diagnostic methods for coronavirus disease-2019 (COVID-19) are the main goals in this study, and the author utilizes the standards set out in the Preferred Reporting Item for Systematic Review and Meta-Analyses (PRISMA) guidelines. A systemic search was performed by one independent reviewer based on PubMed and Google Scholar in July 2021 using the following search terms: “Saliva” OR “saliva assay” AND “diagnosis” AND “COVID-19” OR “SARS-CoV-2” in PubMed. Notably, saliva contains a collection of analytes that show potential to be biomarkers for clinical and translational applications; hence, saliva can be used as an effective biofluid in clinical diagnostics. The passive droll saliva technique may be more homogenous than spitting, and it also can prevent the impact of the inhibitory substance. Saliva specimens are beneficial to the safety of healthcare professionals; these specimens can be a substantial source of virus in saliva for dental professionals, especially in the primary stages of illness, and cotton and calcium alginate swabs may contain compounds that interfere with polymerase chain reaction (PCR) testing and render some viruses inactive. Based on some of the above statements, the collection of only saliva can be used as an alternative specimen during the early stages of symptoms for the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).