# Rapid point-of-care quantification of high-sensitivity C-reactive protein in pulpal blood as an objective biomarker for irreversible pulpitis: a pilot diagnostic accuracy study

## TL;DR

This pilot study explores using a point-of-care test for high-sensitivity C-reactive protein in pulpal blood to objectively diagnose irreversible pulpitis, showing strong correlation with pain intensity.

## Contribution

The study introduces a novel point-of-care fluorescent immunoassay for rapid hs-CRP quantification in pulpal blood as a potential biomarker for irreversible pulpitis.

## Key findings

- hs-CRP levels in pulpal blood strongly correlated with pain intensity (ρ = 0.918, p < 0.01).
- A 3.4 mg/L hs-CRP threshold showed 100% sensitivity and 89% specificity for severe pain.
- Monte Carlo analysis confirmed robust specificity (median 83%) despite imperfect clinical references.

## Abstract

The diagnosis of irreversible pulpitis relies on subjective clinical criteria and low-specific sensitivity tests, potentially leading to inappropriate treatment decisions. High-sensitivity C-reactive protein (hs-CRP) is locally expressed in inflamed pulp tissues and may provide objective diagnostic information. This pilot study evaluated the construct validity of rapid hs-CRP quantification using a point-of-care fluorescent immunoassay (FIA) in pulpal blood and its capacity to discriminate clinically relevant inflammatory phenotypes. Thirteen adult patients with a clinical diagnosis of symptomatic irreversible pulpitis were prospectively enrolled. No healthy or reversible control group included. Pulpal blood hs-CRP was quantified using point-of-care FIA (Finecare FIA Meter Plus) during endodontic access. Pain intensity was assessed using visual analog and categorical ordinal scales. Median hs-CRP was 2.9 mg/L (IQR 0.0–3.5). Very strong correlation was observed between hs-CRP and pain intensity (ρ = 0.918, p < 0.01, 95% CI 0.73–0.99). ROC analysis for severe pain yielded AUC = 0.944 (95% CI 0.82–1.00). The 3.4 mg/L threshold demonstrated 100% sensitivity, 89% specificity, a positive likelihood ratio of 9.33, and a negative likelihood ratio of 0.06. Monte Carlo sensitivity analysis correcting for imperfect clinical reference standards revealed robust specificity (median, 83%) and moderate sensitivity (median, 56%). Point-of-care hs-CRP quantification in pulpal blood represents an objective biomarker with excellent construct validity and discriminative capacity for identifying intense inflammatory phenotypes of irreversible pulpitis in this pilot study. These preliminary findings warrant validation in larger multicenter studies with composite reference standards before clinical implementation can be considered.