The diagnosis of traumatic brain injury (TBI) in the acute setting is based on neurological examination and neuroimaging tools such as CT scanning and MRI. However, CT scanning has low sensitivity to diffuse brain damage and confers exposure to radiation. On the other hand, MRI can provide information on the extent of diffuse injuries but its widespread application is restricted by cost, the limited availability of MRI in many centers, and the difficulty of performing it in physiologically unstable patients. Although some patients with Mild traumatic brain injury (mTBI) may be admitted to the hospital overnight, the vast majority are treated and released from emergency departments with basic discharge instructions. This group of TBI patients represents the greatest challenges to accurate diagnosis and outcome prediction. The lack of clinical tools to detect the deficits that affect daily function, have left these individuals with little or no treatment options. The injury is often seen as “not severe” and subsequently therapies have not been aggressively sought for MTBI. The diagnostic and prognostic tools for risk stratification of TBI patients are therefore limited in the early stages after injury. Unlike other organ-based diseases where rapid diagnosis employing biomarkers from blood tests are clinically essential to guide diagnosis and treatment, there are no rapid, definitive diagnostic blood tests for TBI. Over the last decade there has been a myriad of studies exploring many promising biomarkers. Despite the large number of published studies there is still a lack of any FDA-approved biomarkers for clinical use in adults and children. There is now an
important need to validate and introduce them into the clinical setting. This chapter will review some of the most widely studied biomarkers for TBI in the clinical setting, with an emphasis on those that have been evaluated in MTBI.