A system and method for assessing a patient includes a portable device for measuring a plurality of autonomic nervous system activities so as to form a baseline profile in a processor connected to the device. The baseline profile corresponds to an initial patient status before an impact event. A biomarker profile is determined by a parasympathetic ANS measurement and parasympathetic and sympathetic ANS measurement based on the baseline profile and a projected patient status for a traumatic brain injury. The device measures the plurality of autonomic nervous system activities after an impact event so as to form a test profile. The test profile is compared to the biomarker profile in a memory of the processor so as to form an injury index. When the injury index is equal or greater than a predetermined level, a traumatic brain injury is detected. An interactive display can indicate the traumatic brain injury.
