Accuracy of saliva tests for SARS-CoV-2 diagnosis during the pandemic in Rio de Janeiro, Brazil.

ABSTRACT: Saliva is a promising non-invasive alternative to nasopharyngeal swabs (NPS) for SARS-CoV-2 diagnosis, yet its longitudinal performance remains underexplored. This longitudinal study evaluated saliva's diagnostic accuracy against NPS in 72 symptomatic individuals across six visits (July 2021-May 2022), analyzing 285 paired RT-qPCR samples in Rio de Janeiro, Brazil. Using NPS as the reference standard, saliva demonstrated high specificity (96.6%; 95% CI 92.9-98.7%), substantial agreement (91.6%; κ = 0.78; 95% CI 70-86% ; P < 0.001), and variable sensitivity (69.2% overall; 95% CI 57.2-79.5%), ranging from 40% during mid-phase infection (visit 3) to 82% during early infection (visit 1). Cycle threshold (Ct) values revealed slightly higher viral loads in NPS (mean Ct = 26.75) than in saliva (

SUBMITTER: Fiorani-Nascimento R 

PROVIDER: S-EPMC12546890 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature