0 unspecified state of consciousness

1 with no loss of consciousness

2 with brief [less than one hour] loss of consciousness

3 with moderate [1-24 hours] loss of consciousness

4 with prolonged [more than 24 hours] loss of consciousness and return to pre-existing conscious level

5 with prolonged [more than 24 hours] loss of consciousness, without return to pre-existing conscious level

Use fifth-digit 5 to designate when a patient is unconscious and dies before regaining consciousness, regardless of the duration of the loss of consciousness

6 with loss of consciousness of unspecified duration

9 with concussion, unspecified