Validation of A Non-Invasive Physiological Stress and Inflammatory Assessment: Agreement of Salivary and Blood Biomarkers Among First Responders.

Gonzalez, Drew E; Martin, Steven E; McAllister, Matthew J · J Occup Environ Med · 2026

cross_sectional · Level IV

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Abstract

This study examined blood and saliva cortisol (CORT), interleukin-6 (IL-6), and C-reactive protein (CRP) in first responders to evaluate the accuracy and practicality of using saliva samples in operational contexts. Data from 207 first responders were analyzed. Spearman's correlation, simple linear regression models, and Bland-Altman analyses were performed. Salivary CORT (ρ = 0.713, p < 0.001) closely aligned with blood CORT, accounting for nearly half of the variance and showing narrow Bland-Altman limits. Salivary CRP (ρ = 0.306, p < 0.001) and IL-6 (ρ = 0.281, p = 0.007) exhibited weak correlations and poor agreement. Overall, while salivary CORT is practical for non-invasive monitoring in operational settings, caution is warranted with salivary CRP and IL-6, which need further research as blood substitutes.