Blood tests for concussions – The future, not the present, test

The professional football season has come to a close and another season is behind us in Philadelphia, but the debate over the treatment and management of a common football injury – concussion – will linger well into the next sports season. The diagnosis of concussion on the football sidelines is often easy for a team physician because there are features and examination findings that a sports medicine doctor knows to look for without further testing. The one area of question and concern for players and coaches is when a player will be able to return. If a player sprains his or her ankle, I can grade the sprain and predict return to play within a day or two. Return to play for concussion prediction is not as easy. What isn't debated is that a player suffering from a concussion should not return to play (RTP) the same day. If only we had a method or test to determine how long that athlete will need to stay out.

Concussions are common. For high school athletes, there is a good estimation of 150,000 concussions per year in organized high school sports, and 40% of these are from football. Furthermore, there are an estimated 300,000 sports-related concussions from all sports in athletes 15-24 years of age. The data reveals about a quarter of athletes still have symptoms after a week and 12% are still symptomatic after 10 days. If we could tell people that they will get better by 10 days, it would be very helpful. And for that, a blood test would seem to be ideal.

More research on blood tests needed

The trouble with most of our blood tests for predicting recovery time is they have been tested almost exclusively in adult males immediately after a concussion happens. That might be okay for a professional sports team, but almost all high school athletes will not be able to get an immediate blood draw after such an injury. It is more realistic that they will get tested at 48 to 60 hours after injury.

There is great future potential however. I have seen at least 12 different biomarkers (indicators of brain injury) tested in concussions. By next month there will probably be more. A 2014 study done in Swedish male hockey players published in JAMA Neurology by Pashtun Shahim is an excellent study on the biomarkers for concussions. They showed some promising results for certain proteins shown to be elevated in people with brain injuries, T-tau and S-100B. A second study on the same samples by a researcher at Penn tested for a different protein, named SNTF. Those researchers found levels were different in athletes that returned to play in less than 6 days than in those who returned after more than 6 days. The ability to classify a person into less than 6 days or more than six days was good (not great), accurate about 75% of the time.

Two week return to play protocol more realistic

These tests are a great start, but not very helpful as we need to have a better predictor than 75% and we need a predictor for return to play of 2 weeks or more, not 6 days to be useful in most athletes. Also, from this research paper we find that some of the athletes with the highest levels ended up asymptomatic at 6 days.

Here is why we need a predictor of RTP for 2 weeks or more, not 6 days. The return to play guidelines in Pennsylvania and most states for high school would require the athlete to be symptom-free prior to a return to play protocol. This 6 day return to play protocol would require the athlete to be symptom-free by 48 hours for a return in one week. Therefore, we would need a blood test that is accurate, tested in athletes both males and females, people ages 14-21,and that will be accurate when drawn at 48 hours.

Evaluation of symptoms as effective as blood test?

Another thought is that instead of a blood test, an evaluation of the athletes’ symptoms at the time of injury can predict return in 2 weeks. This was tested a decade ago and researchers found that 80% of people with headache for more than 3 hours, difficulty concentrating for more than three hours and retrograde amnesia (forgot what happened immediately prior to the concussion) were symptomatic after a week. Recently, a group of doctors in Boston tested whether they could predict if an athlete was going to still have symptoms at a month and they could not find a pattern of findings at the time of injury that would help them determine delayed recovery of a month or more. These studies point to the fact that we need more work in this area.

Biomarkers are probably the future of concussion management and they may help us one day determine the readiness for return to play. At this time however, they are in the beginning stages. One problem is the biomarkers are still being tested by those who hold the patents on these biomarker tests and therefore have a financial incentive for them to work. That is how science works. First the person tests something and then it is tested by others to see if it holds true. Biomarkers are the future, but do not look for them in the stores today.

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