Neurobiomarkers for Traumatic Brain Injury: Comparison of Serum Values Within 24 Hours of Injury With Glasgow Coma Scale (GCS) Scores in a Prospective Cohort Trial

Abstract

Objective Traumatic brain injury (TBI) is a significant cause of morbidity, disability, and mortality across all age groups, presenting both health and socioeconomic challenges globally. Neuroimaging techniques are crucial for assessing TBI, but their availability is often limited. Investing in point-of-care blood biomarkers, such as neurofilament light (NFL) protein and S100 calcium-binding protein B (S100B), may offer more accessible and reliable information on neuronal injury, assisting in clinical evaluation without compromising sensitivity. The objective of this study was to correlate the serum values of NFL and S100B with the severity of TBI as assessed by the Glasgow coma scale and to evaluate the potential of these markers for early prognostication. Methods A total of 92 TBI patients, categorized into mild (30), moderate (28), and severe (34) cases, admitted to Nizam's Institute of Medical Sciences, Hyderabad, India, from 2019 to 2020, were enrolled. Serum levels of NFL and S100B were measured within 24-36 hours of injury for all participants. Results NFL concentrations were 51.1±12.13, 99.9±31.55, and 251.68±78.28 pg/mL for mild, moderate, and severe TBI patients, respectively. S100B concentrations were 193.47±76.57, 542.9±158.78, and 1882.6±824.8 pg/mL for mild, moderate, and severe TBI patients, respectively. Significant differences were observed in NFL and S100B levels when compared between the groups (p<0.05). On day 0, the values of NFL (p≤0.001) and S100B (p=0.023) were significantly higher in non-survivors compared to survivors in severe TBI. S100B showed AUCs of 0.98 (mild), 0.93 (moderate), and 0.99 (severe); NFL showed AUCs of 0.21, 0.51, and 0.28, respectively. The odds ratio (OR) for S100B in mild TBI was 1.07 (95% CI: 1.00-1.14); all other ORs were close to 1 with 95% CI including 1. Conclusion S100B showed strong diagnostic performance across TBI severities, while NFL demonstrated limited utility based on low AUC values and non-significant ORs. These findings support the use of S100B as a more reliable biomarker for TBI assessment.

Keywords: computerized tomography (ct) scan; glasgow coma scale (gcs); neurofilament light (nfl); non-survivors; s100 calcium-binding protein b (s100b); serum biomarkers; traumatic brain injury (tbi).

Figure 1. ROC curve showing the AUC for S100B and NFL in assessing diagnostic accuracy

ROC curves illustrate the diagnostic performance of S100B and NFL biomarkers across mild, moderate, and severe TBI. S100B demonstrated high diagnostic accuracy (AUC: 0.98-1.00), whereas NFL showed poor discriminative ability (AUC: 0.21-0.51). The dashed line represents the chance level (AUC=0.5). ROC, receiver operating characteristic; NFL, neurofilament light; S100B, S100 calcium-binding protein B; TBI, traumatic brain injury