Young athletes and infants with "shaken baby syndrome" also suffer this concussion-type injury, USA Today reported Friday.
The blood test looks for unique proteins that spill into the blood stream from damaged brain cells.
These kinds of injuries are easy to miss, researchers say, as the damage does not show up on imaging scans and symptoms such as headaches or dizziness are often ignored or downplayed by those suffering the injury.
Army Col. Dallas Hack says the new technique could rival the discovery of unique proteins in the 1970s that help doctors identify heart disease.
"This will in fact do for brain injury what that test did for chest pain," Hack said. "It's going to change medicine entirely."
One study found about 300,000 troops in Iraq and Afghanistan have suffered concussions, mostly from roadside bombs, USA Today reported.