Comprehensive analytical and clinical evaluation of a RNA extraction-free saliva-based molecular assay for SARS-CoV-2

PLoS One. 2022 May 5;17(5):e0268082. doi: 10.1371/journal.pone.0268082. eCollection 2022.

Abstract

Standard SARS-CoV-2 testing protocols using nasopharyngeal/throat (NP/T) swabs are invasive and require trained medical staff for reliable sampling. In addition, it has been shown that PCR is more sensitive as compared to antigen-based tests. Here we describe the analytical and clinical evaluation of our in-house RNA extraction-free saliva-based molecular assay for the detection of SARS-CoV-2. Analytical sensitivity of the test was equal to the sensitivity obtained in other Dutch diagnostic laboratories that process NP/T swabs. In this study, 955 individuals participated and provided NP/T swabs for routine molecular analysis (with RNA extraction) and saliva for comparison. Our RT-qPCR resulted in a sensitivity of 82,86% and a specificity of 98,94% compared to the gold standard. A false-negative ratio of 1,9% was found. The SARS-CoV-2 detection workflow described here enables easy, economical, and reliable saliva processing, useful for repeated testing of individuals.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19 Testing
  • COVID-19* / diagnosis
  • Humans
  • Nasopharynx
  • RNA
  • RNA, Viral / genetics
  • SARS-CoV-2* / genetics
  • Saliva
  • Sensitivity and Specificity
  • Specimen Handling / methods

Substances

  • RNA, Viral
  • RNA