Concussions lead cause a protein (SNTF )to accumulate in brain & bloodstream where it serves as a biomarker for damage.

FTA:

Elevated levels in the blood of the brain-enriched protein calpain-cleaved ±II-spectrin N-terminal fragment, known as SNTF, shortly after sports-related concussion can predict the severity of post-concussion symptoms in professional athletes, new research has found.