Salivary Biomarkers for Diagnosis and Monitoring of Thyroid Diseases: A Systematic Review of Current Evidence.

BACKGROUND

Thyroid hormones have a crucial impact on all physiological systems. Diagnosis of thyroid diseases using salivary biomarkers is an emerging discipline and requires consolidation of existing information.

AIMS: This systematic review is aimed at identifying and analyzing salivary biomarkers that are associated with thyroid diseases and evaluate their potential as diagnostic applicability as non-invasive indicators of thyroid dysfunction.

METHODOLOGY: Literature search was conducted in PubMed, Cochrane, EBSCO, ProQuest, and Google Scholar from date of inception to May 2025. Human observational studies, clinical trials, and diagnostic accuracy studies published in the English language, that related biomarkers in saliva to thyroid diseases were collected and analyzed for relevant information. The search resulted in 35 records, followed by PRISMA 2020 compliant screening which resulted in 9 records included for data synthesis. Data extraction, tabulation and Risk of Bias assessment was carried out by 2 independent reviewers.

RESULTS

Included studies suggest that FT3, amino acids, salivary metabolic profiling, glycan profiles, microbiome, and thyroid antibodies present in saliva could be putative and noninvasive biomarkers of diagnostic and prognostic importance.

CONCLUSION

Heterogeneity in study design and analytical techniques has limited definitive conclusions about said markers, necessitating future well-designed clinical studies for validation of these biomarkers for noninvasive thyroid screeing and diagnosis.