Prognostic ability of salivary S100B in predicting unfavorable outcomes in patients with moderate and severe traumatic brain injury.

INTRODUCTION

S100B is the most studied biomarker for prognosis of traumatic brain injury (TBI), and saliva is a promising matrix. This study evaluated the prognostic value of S100B in saliva and plasma after moderate to severe traumatic brain injury (TBI).

METHODS

A prospective cohort included 25 adult patients (18-60 years) admitted to three hospitals with a Glasgow Coma Scale score of 3 to 12 within four hours post-trauma. Saliva and plasma samples were collected three hours after the trauma, with an additional saliva sample collected at six hours. Outcomes were assessed using the Glasgow Outcome Scale at discharge and its extended version.

RESULTS

Plasma S100B levels were higher than salivary (p = 0.0113) and decreased significantly between 3 and 6 hours (p < 0.0001). Salivary S100B at 6 hours was significantly higher in patients with unfavorable outcomes (p = 0.0248). Among all measures, salivary S100B at 6 hours demonstrated the highest prognostic accuracy, with an area under the curve (AUC). AUC for salivary S100B was 0.71 at 3 hours and 0.62 at 3 months, compared to 0.66 for plasma.

CONCLUSION

Salivary S100B at 6 hours post-TBI showed superior prognostic performance compared to plasma and earlier saliva samples, highlighting its potential as a noninvasive biomarker for TBI prognosis.