The FDA recommended that consumers use only cleared or approved medical devices to assess or diagnose a head injury, including concussions.

The agency said it discovered several devicemakers marketing devices for diagnosing or assessing concussions—but their devices had not received FDA clearance or approval and could give a false diagnosis.

“The use of unapproved medical devices may lead to an incorrect diagnosis. An incorrect diagnosis of ‘no head injury’ after an injury, for example, could lead a person with a serious head injury to return to their normal activities instead of getting medical care,” the agency said.

Only a “limited number” of devices have earned the agency’s clearance or approval to help manage or detect concussion.