Researchers say this is worrisome.
The job of the ER docs is essentially limited to making sure there is no emergency such as bleeding on the brain.
But it can take days following a concussion that the course of the injury can be assessed. That's when parents can be advised on when their children can safely return to sports or other activities.
The new report estimates that more than 100,000 children visit the emergency room each year for a concussion.