Levels of a blood protein following a concussion could predict how severe the symptoms will be in professional athletes. 

Research suggests looking at levels of the brain-enriched protein, dubbed calpain-cleaved αII-spectrin N-terminal frogmen (SNTF), on the day of a mild traumatic brain injury could indicate risk of axonal injury and long-term cognitive dysfunction, the Perelman School of Medicine at the University of Pennsylvania reported. 

"We extended this biomarker research to the domain of professional sports to test its merit as an objective and rapid way to determine players' severity of brain injury," said lead author, Robert Siman, Research Professor of Neurosurgery at Penn. "This blood test may aid neurobiologically-informed decisions on suitability for return to play following a sports-related concussion."

To make their findings the researchers looked at 288 players in the top Swedish professional ice hockey league. Out of 28 players who had blood drawn on the day of their concussion and received a daily symptom check, eight were symptom-free within a few days of their injury. The other 20 players continued to experience post-concussion symptoms, requiring them to be withheld from playing for at least six days. An additional 45 players who did not sustain concussions were tested as a control group. 

Compared to the players who did not receive concussions, or who had a relatively quick resolution of symptoms, the researchers noticed an elevation of SNTF for between one hour and 144 hours post-concussion in the players that had long-lived symptoms. 

SNTF is present at undetectable levels in the healthy human brain, but levels increase when nerve damage is present. 

"These results show that SNTF has promise as a blood biomarker for sports-related concussion and beyond. High blood levels of SNTF appear to identify acute brain damage that corresponds with persisting symptoms after concussion. These observations lend further support to the growing awareness that concussion is not trivial, since it can induce permanent brain damage in some individuals," agree Siman and senior author, Douglas H. Smith, MD, professor of Neurosurgery and director of the Center for Brain Injury and Repair at Penn.

The findings were published in a recent edition of the Journal of Neurotrauma.