Procalcitonin and C-reactive protein as alternative salivary biomarkers in infection and inflammatory diseases detection and patient care: a scoping review

Background: In ambulatory and hospital settings, inflammatory diseases stand a significant challenge for both patients and clinicians. These conditions, often serve as precursors to sepsis, necessitate effective differentiation between bacterial and viral respiratory diagnoses. Procalcitonin (PCT) and C-Reactive Protein (CRP) have played crucial roles in this differentiation process, aiding in risk stratification and guiding decisions on antibiotic therapy initiation and duration. While blood has been a conventional medium for detecting these biomarkers, there is a lack of evidence regarding their detection in saliva. Hence, our scoping review was aimed to assess the potential of procalcitonin (PCT) and C-reactive protein (CRP) in saliva as alternative biomarkers for identifying and monitoring infectious and inflammatory diseases. Materials and methods: PRISMA guidelines for scoping reviews was followed. Elec-tronic databases including PUBMED, Scopus, Web of Science, Cochrane database, and OVID Medline were systematically searched using specific terms combined with boolean operators. Studies evaluating both salivary and blood levels of PCT, CRP, or both and reporting on correlation in biomarkers level between the two body fluids were included. No limitations regarding study design, publication year and language were applied. Data extraction utilized a piloted template, and descriptive statistics was employed. Results: The studies included in the review involved a range of conditions from respiratory infections and systemic diseases to metabolic and cardiac conditions. Significant correlations between salivary and serum PCT and CRP levels were reported across multiple studies. While most studies reported positive correlations, indicating saliva’s potential to reflect systemic inflammatory states, the degree of correlation varied, and a few studies found no significant correlation, highlighting the need for further research. Conclusion: The review emphasized the promising role of salivary diagnostics to identify systemic inflammatory states, which could prove pivotal in detecting and managing various health conditions. The importance of standardizing saliva collection and biomarker detection methods to enhance non-invasive, patient-centered healthcare approaches is un derscored.