If an adult experiences an acute, sudden onset of chest pain, most people would say that the decision about whether that person had or is having a heart attack should be made by a doctor, that if you suspect something serious is going on, the person should get checked out right away by a medical professional. No smartphone app or test can - or should - take the doctor's place.
The same is true for concussions, say the experts.
If a parent, coach, or game official has reason to suspect that a player has suffered a concussion playing sports, the athlete should be checked out right away by a medical professional.
No matter what anyone may tell you, no smartphone app or sideline test can put a parent or a coach in a position to diagnose a concussion or determine on the sideline that it somehow safe for an athlete to return to play.
That job can ONLY be done by a licensed medical provider.
End of story.