Blood biomarkers for traumatic brain injury: A narrative review of current evidence.

Introduction: A blood-based biomarker (BBBM) test could help to better stratify patients with traumatic brain injury (TBI), reduce unnecessary imaging, to detect and treat secondary insults, predict outcomes, and monitor treatment effects and quality of care.
Research Question: What evidence is available for clinical applications of BBBMs in TBI and how to advance this field?
Material and Methods: This narrative review discusses the potential clinical applications of core BBBMs in TBI. A literature search in PubMed, Scopus, and ISI Web of Knowledge focused on articles in English with the words "traumatic brain injury" together with the words "blood biomarkers", "diagnostics", "outcome prediction", "extracranial injury" and "assay method" alone-, or in combination.
Results: Glial fibrillary acidic protein (GFAP) combined with Ubiquitin C-terminal hydrolase-L1(UCH-L1) has received FDA clearance to aid computed tomography (CT)-detection of brain lesions in mild (m) TBI. Application of S100B led to reduction of head CT scans. GFAP may also predict magnetic resonance imaging (MRI) abnormalities in CT-negative cases of TBI. Further, UCH-L1, S100B, Neurofilament light (NF-L), and total tau showed value for predicting mortality or unfavourable outcome. Nevertheless, biomarkers have less role in outcome prediction in mTBI. S100B could serve as a tool in the multimodality monitoring of patients in the neurointensive care unit.
Discussion and Conclusion: Largescale systematic studies are required to explore the kinetics of BBBMs and their use in multiple clinical groups. Assay development/cross validation should advance the generalizability of those results which implicated GFAP, S100B and NF-L as most promising biomarkers in the diagnostics of TBI.
Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Iftakher Hossain reports financial support was provided by The Finnish medical Foundation. Peter Hutchinson reports financial support was provided by 10.13039/501100000297Royal College of Surgeons of England. Iftakher Hossain reports financial support was provided by The 10.13039/501100007417Paulo Foundation. Iftakher Hossain reports financial support was provided by The 10.13039/501100003125Finnish Cultural Foundation. Niklas Marklund reports financial support was provided by 10.13039/501100011077Skåne University Hospital ALF funds. Niklas Marklund reports financial support was provided by 10.13039/501100017237Hans-Gabriel af Trolle Wachtmeister Foundation. Niklas Marklund reports financial support was provided by Swedish 10.13039/501100003792Brain Foundation. Peter Hutchinson reports a relationship with NIHR Cambridge Clinical Research Facility, Addenbrookes Hospital that includes: funding grants.
(© 2023 The Authors.)