Concussions occur when the brain impacts against the inside of the skull, and are one of the most common sports injuries seen by doctors worldwide. Any good doctor will tell you that in order to give yourself the best chances of recovering, you need to treat a concussion early. According to a report from the Washington Post, a new blood test could help pinpoint concussions before they can cause serious brain damage.

Scientists published their findings about the new blood test for concussions in the journal JAMA Neurology on Monday. The study examined 600 patients who had been admitted to a trauma center between 2010 and 2014. Each of the patients had undergone serious head trauma that left them unconscious, disoriented, or struggling with a bout of amnesia.

Scientists took blood samples from the participants as soon as they arrived at the hospital, and again in regular intervals throughout their stay. Researchers were particularly interested in levels of a biomarker called glial fibrillary acidic protein, or GFAP over time.

Blood samples revealed that GFAP levels typically reached a peak 20 hours after the injury and began to decline over a 3-day period. GFAP was detectable in the participants for as long as seven days following the initial injury.

The scientists believe that GFAP could be a consistent indicator of head trauma, which could go a long way toward saving people’s brain cells. Testing for levels of this biomarker could mean the difference between a mild concussion diagnosis and letting an injured person walk with no treatment.

According to the study’s lead author Linda Papa, a physician at Orlando Health, “We have so many diagnostic blood tests for different parts of the body, like the heart, liver and kidneys, but there’s never been a reliable blood test to identify trauma in the brain. We think this particular test could change that.”

The study can be found here.