Key clinical point: Higher levels of total tau protein and lower levels of glial fibrillary acidic protein were both associated with athletes who took longer to return from concussions.

Major finding: Athletes who returned to their sports in 14 days or more had higher total tau levels at 24-48 hours post injury and at the time their symptoms resolved, compared with athletes who returned in less than 14 days.

Study details: A multicenter, prospective diagnostic study of 127 student-athletes who had concussions and then returned to their sports.

Disclosures: The study was supported by the Grand Alliance Concussion Assessment, Research, and Education Consortium, which was funded in part by the NCAA and the Department of Defense. The authors disclosed receiving grants and travel reimbursements from—or working as advisers or consultants for—various organizations, college programs, and sports leagues.