New blood test tracks brain recovery after concussion

A blood test can accurately determine the ongoing effects of sport-induced concussion and help determine when it is safe to return to training, a Monash University-led study has found.

The researchers measured levels of two brain-specific proteins in the blood of 81 Victorian Amateur Football Association (VAFA) players who had suffered a concussion and compared them to 56 players who had not suffered a concussion.

By tracking blood biomarker levels over time, they monitored how long it took for players’ brains to recover, otherwise known as “neurobiological recovery,” to help determine when it may be safe to return to play without increased risk of injury.

Until now, there have been no well-established tools to track neurobiological recovery after sport-induced concussion.

Published in JAMA Network Open, this cohort study examined the dynamics of two brain cell proteins, glial fibrillary acidic protein (GFAP) and neurofilament light protein (NfL), which are released into the blood following brain injury.

While the team’s previous studies had demonstrated the diagnostic potential of these biomarkers in the blood, this study aimed to show how their levels changed over time in concussed players.

The most striking finding was the variety of biomarker changes across individuals, with more than 20% of concussions showing significant and sustained increases in both GFAP and NfL, which remained elevated compared to uninjured footballers for more than four weeks.

Individuals with these extreme biomarker changes were significantly more likely to suffer a loss of consciousness following a head impact.

Study leader and principal investigator of the Monash Trauma Group, Dr Stuart McDonald, from Monash University’s School of Translational Medicine, noted that while his The team and others have studied these biomarkers previously, making this the first time a complete profile of post-injury progression has been recorded.

“What’s unique about this study isn’t the measurement itself, but how many times and how consistently we performed it – eight times over six months across 137 athletes,” said Dr. McDonald. “With very little missing data due to our unique approach of visiting participants at home, we were able to obtain a detailed profile of biomarker trajectories over time.”

“We’ve demonstrated that blood GFAP levels are elevated in the vast majority of concussed athletes at 24 hours, and we’re now working to get this much-needed diagnostic test approved for use in the coming years.”

"The next important step is to demonstrate how and when we should measure these two proteins as biomarkers for return to play. Our findings bring us closer to making this a reality.

"Our vision is for serial measurements of these proteins to be integrated into clinical practice, guiding return-to-play decisions based on both symptoms and neurobiological recovery."