TABLE A1.

ICD-9 Diagnosis Codes for Concussion^a

Concussion with no loss of consciousness	ICD-9-D-850.0
Concussion with brief loss of consciousness	ICD-9-D-850.1
Concussion with loss of consciousness of 30 minutes or less	ICD-9-D-850.11
Concussion with loss of consciousness from 31 to 59 minutes	ICD-9-D-850.12
Concussion with moderate loss of consciousness	ICD-9-D-850.2
Concussion with prolonged loss of consciousness and return to pre-existing conscious level	ICD-9-D-850.3
Concussion with prolonged loss of consciousness without return to pre-existing conscious level	ICD-9-D-850.4
Concussion with loss of consciousness of unspecified duration	ICD-9-D-850.5
Concussion unspecified	ICD-9-D-850.9

^aICD-9, International Classification of Diseases–9th Revision.