EMBARGOED FOR RELEASE UNTIL 4 PM ET, July 08, 2020
Simple Blood Test May Predict Concussion Severity Just as Well as Spinal Tap
Two-Pronged Study Included Professional Hockey Players
MINNEAPOLIS 鈥 A blood biomarker in people who have had concussions may be just as accurate at predicting the severity of the injury and how long it will last as biomarkers that are obtained through more expensive and invasive tests, according to a study published in the July 8, 2020, online issue of , the medical journal of the 好色先生. The study looked at a biomarker called neurofilament light chain, a nerve protein that can be detected in the blood and cerebrospinal fluid when nerve cells are injured or die. 鈥淲hen your brain is injured, neurofilament light chain levels are higher in both your blood and your spinal fluid,鈥 said study author Pashtun Shahim, M.D., Ph.D., of the National Institutes of Health Clinical Center in Bethesda, Md. 鈥淢easuring this biomarker in your blood with a simple blood draw is faster and easier than measuring it your spinal fluid, which requires a more invasive spinal tap. Our findings are exciting because they show that the simple test may also be just as accurate for determining how severe the injury is and predicting how you might do long term.鈥 The study involved two groups of people with head injuries. The first group consisted of 104 professional Swedish hockey players. This group鈥檚 median age was 27 and included 45 athletes who had a concussion within the past week, 31 athletes with who had multiple concussions, 28 athletes with no recent concussion or symptoms and 14 healthy people who weren鈥檛 athletes. All of the participants had the biomarker levels in their blood tested. The 31 athletes with multiple concussions and the 14 healthy controls also had the biomarkers in their spinal fluid tested through spinal taps. Researchers found that the amount of the biomarker in the athletes鈥 blood was similar to the level in their spinal fluid. Biomarker levels were different in participants who had no concussions, concussions less than a year before or concussions more than a year before. The athletes with multiple concussions had a median of 18 picograms/milliliter (pg/mL) of the protein biomarker their blood, those with recent concussions had 12 pg/mL, the athletes with no recent concussions or symptoms had 10 pg/mL and the healthy non-athletes had 9 pg/mL. These levels correlated well with the levels researchers found in their spinal fluid. Further, the biomarker levels in the hockey players鈥 blood correlated strongly with more concussions and more severe concussions, even a year after the injury. The second group, based at the National Institutes of Health Clinical Center, had an average age of 43 and included 162 people with brain injuries and 68 healthy people. Researchers examined the role of the biomarker in distinguishing between mild, moderate and severe concussions. In the clinic-based study, the group with head injuries had a median of 12.8 pg/mL of the biomarker in their blood, while the healthy control group had 6.3 pg/mL. Again, those levels correlated closely with levels detected by more sophisticated tests like brain imaging. The level of biomarker in the blood accurately let researchers distinguish between mild, moderate and severe concussions. The difference in biomarker levels between people with concussions and the healthy controls was found up to five years after the concussion. 鈥淚n both of our studies, the same idea came through: Neurofilament light chain shows great promise as a biomarker in the blood,鈥 Shahim said. 鈥淭his is notable because the test may help us identify people whose concussions might give them debilitating symptoms for years after the injury. And that may help doctors treat their patients more specifically for the type of concussion they have.鈥 鈥淚n order to implement these results into clinical practice, larger studies will be needed to determine how neurofilament light chain changes across the spectrum of traumatic brain injury and in different populations,鈥 said Shahim. This study was supported by the National Institutes of Health, the Department of Defense, the Center for Neuroscience and Regenerative Medicine at the Uniformed Services University, and the Swedish Research Council. Learn more about concussion and brain injury at, home of the 好色先生鈥檚 free patient and caregiver magazine focused on the intersection of neurologic disease and brain health. Follow Brain & Life庐 on , and . When posting to social media channels about this research, we encourage you to use the hashtags #Neurology and #AANscience.