Applicability of S100B in the Screening of Intracranial Injury in Patients With Mild Traumatic Brain Injury Intoxicated With Alcohol

Background Traumatic brain injury (TBI) frequently occurs in patients with ethanol intoxication (EOI), complicating cranial CT evaluation. Therefore, it is necessary to identify simple alternative biomarkers of intracranial lesions (ICL). This study assesses whether the biomarker S100B can help rule out ICL in patients with mild TBI and EOI, according to Scandinavian TBI guidelines. Method An observational study with cross‐sectional data collection was conducted at Son Llàtzer University Hospital (HUSLL), in Palma de Mallorca, including patients aged 18–65 years who sustained mild TBI in the context of EOI ( n = 116), had an inconclusive Glasgow Coma Scale (GCS) score, and presented to the Emergency Department within 6 h of injury. Blood samples were collected to measure S100B and blood alcohol levels. All patients underwent cranial CT (the gold standard). CT results (positive/negative for ICL) were compared with S100B values, dichotomized at ≤ 0.1 μ g/L. Results The primary objective was to analyze the relationship between S100B levels (≤ 0.1 μ g/L vs. > 0.1 μ g/L) and cranial CT results. In 97.8% of patients with a negative CT result, S100B levels were ≤ 0.1 μ g/L. Conversely, among those with S100B > 0.1 μ g/L, 12.7% had a positive CT result ( χ 2 = 3.82, df = 1, p = 0.04; OR = 6.38; 95 % CI = 1.01–52.25). S100B demonstrated a high sensitivity of 90% for detecting ICL, with a specificity of 42%, a positive predictive value of 13%, and a negative predictive value of 98%. Conclusion S100B appears to be a sensitive biomarker for ruling out ICL in mild TBI. Levels ≤ 0.1 μ g/L were associated with negative CT findings, whereas higher levels showed limited positive predictive value. S100B may help reduce unnecessary CT imaging in low‐risk patients; however, its limited specificity requires interpretation within the clinical context.