There is a growing interest for the study of blood biomarkers to aid in the clinical diagnostics and care of TBIs. Despite years of research, none has reached wider clinical use or e.g. FDA approval. This symposium aims to give an overview about the challenges in TBI biomarker development as well as current status on the most studied candidate markers. The aspects presented will give information also about the pathobiology of TBI, such as the role of the blood-brain-barrier and glymphatic system. The aim of this session is to give the audience a more comprehensive and very updated view about the prospects of blood biomarker diagnostics in TBI, as well as give an overview about the challenges in TBI biomarker development and the current status of the most studied candidate markers. In addition to this, new possibilities will be discussed.