The invention relates to methods for providing prognosis, diagnosis, monitoring and treatment of a mild traumatic brain injury (mTBI) in a subject, including a sports-related concussion. The invention further relates to assessing the severity of brain damage resulting from mTBI in a subject, including in a subject who has not undergone a CT scan following the injury. For example, the methods of the invention can be used to determine the suitability for someone who has suffered a sports-related injury to return to play that sport. This invention also relates to methods of predicting risk for developing brain damage and long-term dysfunction in a subject having suffered mTBI.