About 400,000 high school and college athletes suffer a concussion each year. It’s not surprising to find out that football players are most at risk. In fact, at least one player suffers a mild concussion in each game, but did you know that you can get hit hard, not sustain a concussion, and still put your brain at risk? 

Now, there’s a new test that can show within seconds if a player should be pulled from the game, even if he or she doesn't have a concussion.

"I’ve been hit hard hundreds or thousands of times," said Zach Barley, a Baldwin College senior who has taken some hard hits over the years.

Number 29 was once pulled from a game after suffering a concussion, but you don’t have to be hit that hard to damage your brain. There’s now something called a sub-concussive hit.

Cleveland Clinic and the University of Rochester developed a blood test taken before, during, and after a game to find out if those hits can damage the blood brain barrier, the lining in each of the blood vessels in your brain that prevents harmful molecules from getting in. When a player is hit hard, that barrier is breached.

"The blood test is based on a molecule called S100B, which is present in the brain but not in blood. When the barrier breaches, the molecule shows up in the blood," said Dr. Damir Janigro, director in cerebrovascular research at Cleveland Clinic's Lerner Research Institute.

And the immune system attacks it.

"The body believes there is a pathogen, bacteria, a fungus, or some other enemy to fight. So the body fights the enemy," Janigro said.

Then it goes into the brain and can attack brain tissue, similar to what happens with Alzheimer's patients.

Right now, Barley's brain is intact, "but I’m not willing to risk my life over playing a game," Barley said.

This test could mean he and other players won't have to.

Before, doctors used MRI to see damage from concussion and sub-concussion, but it's not as sensitive as the blood test. Researchers hope to continue developing the blood test and one day have it used on the sidelines of every game.

DOWNLOAD and VIEW research summary

DOWNLOAD and VIEW the full-length interview with Dr. Damir Janigro about a new concussion test to keep athletes safe