R40.2323
Coma scale, best motor response, extension, at hospital admission
R40.2323 (also written R402323) is a billable ICD-10-CM diagnosis code for coma scale, best motor response, extension, at hospital admission. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 101 codes in category R40 (Somnolence, stupor and coma). The Alphabetic Index lists it under 4 entries. Its 7th character, 3, means at hospital admission. Its coding notes include a Code first instruction, 4 Excludes1 entries and 5 Excludes2 entries.
7th character
Category R40.23 requires a 7th character.
Guidelines tips
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
Pressure ulcer stage, ulcer depth, BMI, NIHSS and coma scale may be coded from other clinicians' documentation. The diagnosis itself must be documented by the patient's provider.
Symptom and sign codes are acceptable when no definitive diagnosis has been established. They are not added for signs that are routinely associated with a diagnosis.
R40.20 is for coma of unknown cause or traumatic brain injury without a documented scale. Coma scale codes are not reported for a medically induced coma or a sedated patient.
Code first
If the underlying condition listed here is present and known, sequence it first.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (5 notes)
- symptoms and signs constituting part of a pattern of mental disorder (F01-F99)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Hospice: not accepted as primary
Not accepted as the principal diagnosis on a hospice claim (bill types 081x and 082x). The Integrated OCE returns an edit for this code.
Reason: Supplementary or additional code, not allowed as principal diagnosis.
Hospital MCC
Counts as a major complication or comorbidity (MCC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 718 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.
Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix CInclusion terms
Conditions classified to this code.
- Abnormal extensor posturing to pain or noxious stimuli (< 2 years of age)
- Coma scale motor score of 2
- Extensor posturing to pain or noxious stimuli (2-5 years of age)
Notes
Also from chapter/block level (9 notes)
- This chapter includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill-defined conditions regarding which no diagnosis classifiable elsewhere is recorded.
- Signs and symptoms that point rather definitely to a given diagnosis have been assigned to a category in other chapters of the classification. In general, categories in this chapter include the less well-defined conditions and symptoms that, without the necessary study of the case to establish a final diagnosis, point perhaps equally to two or more diseases or to two or more systems of the body. Practically all categories in the chapter could be designated 'not otherwise specified', 'unknown etiology' or 'transient'. The Alphabetical Index should be consulted to determine which symptoms and signs are to be allocated here and which to other chapters. The residual subcategories, numbered .8, are generally provided for other relevant symptoms that cannot be allocated elsewhere in the classification.
- The conditions and signs or symptoms included in categories R00-R94 consist of:
- (a) cases for which no more specific diagnosis can be made even after all the facts bearing on the case have been investigated;
- (b) signs or symptoms existing at the time of initial encounter that proved to be transient and whose causes could not be determined;
- (c) provisional diagnosis in a patient who failed to return for further investigation or care;
- (d) cases referred elsewhere for investigation or treatment before the diagnosis was made;
- (e) cases in which a more precise diagnosis was not available for any other reason;
- (f) certain symptoms, for which supplementary information is provided, that represent important problems in medical care in their own right.
Alphabetic Index terms
Terms the official Alphabetic Index lists for R40.232. This code adds the 7th character. 4 entries