Determination of Blood Biomarkers in Mild Traumatic Brain Injury (mTBI), GFAP and UCH-L1, in Patients Admitted to the Emergency Department with Suspected Mild TBI

Introduction: Traumatic brain injury (TBI) is one of the most common conditions in the emergency department (ED), representing a public health issue with substantial economic impact. The risk of severe acute intracranial injury increases the need for cranial computed tomography (CT). Serum biomarkers of acute brain injury, such as glial fibrillary acidic protein (GFAP) and ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1), have emerged as potential alternatives. Methods: This was a screening study conducted in the ED in 2024. Adult patients admitted with mild TBI within 12 hours of injury, and meeting the criteria for cranial CT were included. For each participant, UCH-L1 and GFAP levels were assessed. The cranial CT scan was considered positive in the presence of brain injury. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were estimated for the presence of both biomarkers combined and separately for UCH-L1 and GFAP. Results: A total of 315 patients were enrolled, and 13 were excluded for not meeting the inclusion criteria. Acute traumatic intracranial lesions were diagnosed in 14 patients (4.6%). The use of UCH-L1 alone yielded a sensitivity of 50% and a NPV of 96%. GFAP demonstrated a sensitivity of 100% and a NPV of 100%. When considering the positivity of both biomarkers, sensitivity and NPV remained at 100%, with a potential reduction in cranial CT scans of 23.2%. Conclusion: The findings of this study suggest that these serum biomarkers may be used to reliably rule out brain injury in patients with mild TBI, providing a strong level of confidence.