Given there is no simple test to diagnose a concussion, the process takes several steps:
Interview conducted by a medical provider asking about the event and mechanism leading to the head injury. They will also ask about current symptoms, co-occurring injuries, pre-existing medical conditions, including mental health conditions, previous concussions, and course of symptoms since the time of injury.
Examination for any neurologic signs or symptoms, including tests of strength, vision, eye movements, hearing, reflexes, balance, coordination, mental status and cognition, and other neurological functions.
Imaging is not recommended to diagnose a concussion. This is because most of the effects of a concussion are not able to be seen on imaging. If more serious symptoms are present, such as loss of consciousness, seizures, severe headache, etc., or symptoms worsen, a CT scan may be appropriate to rule out a more serious head injury.