R40.23Coma scale, best motor response

R40.23 is the ICD-10-CM diagnosis code for coma scale, best motor response. It belongs to category R40 (Somnolence, stupor and coma), block R40-R46 (symptoms and signs involving cognition, perception, emotional state and behavior) and chapter 18 (symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified). It is a header code, so it can't be reported by itself; one of its 6 subcodes must be used instead.

Within R40.2 (coma), R40.23 is specifically for coma scale, best motor response. Related codes cover unspecified coma (R40.20), scale, eyes open (R40.21), scale, best verbal response (R40.22), Glasgow coma scale, total score (R40.24) and nontraumatic coma due to underlying condition (R40.2A).

Codes in this range require a 7th character: 0 for unspecified time, 1 for in the field [EMT or ambulance], 2 for at arrival to emergency department, 3 for at hospital admission and 4 for 24 hours or more after hospital admission. Use placeholder "X" characters to fill any empty positions before the 7th character.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.