Diagnostic and Prognostic Significance of the S100 Biomarker in Blast-related Closed Traumatic Brain Injury

Traumatic Brain Injury (TBI) is a frequent cause of long‑term disability in service members who have been exposed to blast, and clinicians often lack reliable tools to quantify the actual burden of damage early after injury. Among available candidates, S100B is a calcium‑binding protein of astroglial origin that appears in the bloodstream when the blood-brain barrier is disrupted, and neuronal structures are injured. Its diagnostic and prognostic properties in the specific setting of blast‑related closed TBI, however, remain incompletely defined. The present study, therefore, focuses on military personnel with blast‑related closed TBI and examines the diagnostic and prognostic significance of serum S100 by tracking its concentration at several post‑injury time points across predefined severity groups.

A prospective cohort of military patients with blast‑related closed TBI was examined, and serum S100 concentrations were measured at 1, 3, 6, and 12 hours after injury. Patients were stratified into mild, moderate, and severe TBI categories, and S100 dynamics were analysed in relation to these severity groups using standard descriptive statistics, group‑comparison tests, ROC analysis, correlation analysis, and K‑means clustering, as detailed in the Methods section.

Serum S100 levels peaked at 6 hours after trauma and showed a moderate correlation with TBI severity (r = 0.65, p < 0.001). Statistically significant differences in S100 concentrations were found between severity groups at all investigated time points (p < 0.001), and ROC analysis yielded an AUC of 0.81 for severity discri-mination. Diagnostic performance indices (AUC, optimal cutoff, sensitivity, specificity, positive and negative predictive values, and overall accuracy with 95% confidence intervals) are summarised in the Results, and K‑means clustering revealed distinct patient subgroups with different temporal S100 profiles, indicating the feasibility of more personalized risk stratification and management.

These findings support the use of S100 as a clinically relevant biomarker for early grading of blast‑related closed TBI and short‑term outcome prediction. Incorporating S100 into multimodal assessment algorithms may improve risk stratification and guide timely therapeutic decisions in affected patients.

S100 can be considered a useful biomarker for early grading of brain injury severity and outcome prediction in blast‑related closed TBI. Integration of S100 into multimodal diagnostic algorithms has the potential to improve stratification of patients, inform therapeutic decision‑making, and enhance outcomes in military and civilian populations exposed to blast trauma.