Photo: AP

Concussions are tricky business for several reasons. First, although sometimes it’s obvious when an athlete has taken a serious blow to the head and needs to sit out, on many occasions the extent of an injury isn’t so clear. Players who’ve taken a hit may not want to leave the game, so they won’t always report an injury. Coaches want to protect their players, but they also want to put their best players on the field—especially when a player insists that he or she is “fine.”

All of this creates opportunities for players to step into a game when they shouldn’t. The risk could be averted if there were a reliable test that could confirm conclusively whether a concussion has occurred. Well, according to research published in the journal PLOS One, such a test may be available soon—and it’s as simple as a pinprick.

Scientists have known that elevated levels of S100B, a protein in the blood, can indicate a traumatic brain injury. However, S100B levels also become elevated after physical exertion, making it difficult to determine whether the increase is due to a concussion or to intense activity.

In the study, researchers first took blood samples to determine the baseline levels of S100B in 46 athletes, who ranged in age from 18 to 30 and played sports including hockey, basketball, football and soccer. The samples needed were small, taken with a simple pin prick of the finger. The study’s authors then tested 30 of the athletes (all hockey players) after exertion, which took the form of non-contact ice hockey skating drills. Researchers found that S100B levels in these athletes only rose approximately 2% compared to their baselines.

Twenty-two of the same hockey players suffered clinically confirmed concussions during their seasons, and in 17 of those instances, researchers were able to take another blood test within three hours of the concussion event. These tests showed a far more significant spike in S100B levels—the average increase was 81%. Based on these tests and other findings, researchers determined that a 45% or greater increase in S100B could conclusively indicate a concussion.

Jeffrey J. Bazarian, M.D., professor at the University of Rochester and one of the researchers who conducted the study, said, “[45% is] the percent increase in the S100B blood test where the probability of concussion in this group was very high (about 97%). Smaller increases [of S100B] in the blood test were associated with a lower probability that an individual athlete had suffered a concussion.”

For the blood test to work, athletes would need to record their baseline levels of S100B with their teams, presumably before the season. And although the research seems promising, no timetable currently exists for making S100B testing widely available. “It really depends on when the FDA approves the test,” said Dr. Bazarian. “So far no diagnostic test for traumatic brain injury has been approved, and confidentiality rules prevent the FDA from commenting on the issue.”