That gap is not a failure of any one hospital. It reflects how mild TBI presents. Symptoms can be subtle at first, standard CT scans are often normal even when injury is present [], and emergency departments are built to rule out life-threatening bleeding, not to characterize the full injury.
The science of brain injury assessment has moved quickly in the past decade. The FDA has cleared blood tests that measure proteins released by injured brain cells [, , , ]. The National Academies of Sciences, Engineering, and Medicine have called for TBI classification that incorporates blood biomarkers and imaging and is updated as a patient's condition evolves []. A new national framework published in 2025 makes biomarkers one of four pillars of TBI characterization []. Consensus diagnostic criteria now recognize elevated blood biomarkers as supportive laboratory findings [].
This section of our site explains that science in plain language, with every claim linked to the published research or federal source behind it. It exists so that patients, families, and referring providers can see the evidence for themselves.
Diagnosis is always made by a physician through clinical examination. The tests described here substantiate clinical findings. They do not replace the physician, and no test result by itself establishes or excludes a brain injury [].
Explore the research: How TBI classification is changing. Blood biomarkers, explained. What the research shows about timing. Why a normal scan does not rule out injury. How common lasting symptoms are. Vision and balance testing. Laboratory standards. The research library.