2027 ICD-10-CM Diagnosis Code R40Somnolence, stupor and coma

ICD-10-CM Codes›R00–R99›R40-R46›R40

ICD-10-CM R40
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

R40 is a non-billable ICD-10-CM category code for somnolence, stupor and coma, so it cannot be submitted on claims. Use a more specific code from this category instead, such as R40.0, R40.1, R40.20, and R40.2110. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established.

Code Identity

ICD-10-CM Code
R40
Billable Status
No — Non-Billable Category
Code Describes
Somnolence, stupor and coma
Short Description
Somnolence, stupor and coma
Same as the full description in the CMS dataset.
Chapter
R40-R46
Symptoms and signs involving cognition, perception, emotional state and behavior

Code Classification

ChapterR00–R99Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
SectionR40-R46Symptoms and signs involving cognition, perception, emotional state and behavior
CategoryR40Somnolence, stupor and coma
This CodeR40Somnolence, stupor and coma

Specific Coding for Somnolence, stupor and comaOverview

Non-specific codes like R40 require more characters. Use one of these billable codes instead:

  • Use R40.0 for Somnolence

  • Use R40.1 for Stupor

  • R40.2 for Coma

  • Use R40.20 for Unspecified coma

  • R40.21 for Coma scale, eyes open

  • R40.22 for Coma scale, best verbal response

  • R40.23 for Coma scale, best motor response

  • R40.24 for Glasgow coma scale, total score

  • Use R40.2A for Nontraumatic coma due to underlying condition

  • Use R40.3 for Persistent vegetative state

  • Use R40.4 for Transient alteration of awareness

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to R40: its own notes plus those printed at block R40-R46 and Chapter 18. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • neonatal coma (P91.5)
  • somnolence, stupor and coma in diabetes (E08-E13)
  • somnolence, stupor and coma in hepatic failure (K72.-)
  • somnolence, stupor and coma in hypoglycemia (nondiabetic) (E15)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Block R40-R46 Symptoms and signs involving cognition, perception, emotional state and behavior applies to 157 codes
  • symptoms and signs constituting part of a pattern of mental disorder (F01-F99)
From Chapter 18 (R00-R99) Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified applies to 774 codes
  • abnormal findings on antenatal screening of mother (O28.-)
  • certain conditions originating in the perinatal period (P04-P96)
  • signs and symptoms classified in the body system chapters
  • signs and symptoms of breast (N63, N64.5)

Notes

General instructions on how these codes are used.

From Chapter 18 (R00-R99) Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified applies to 774 codes
  • 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.

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name R40, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming R40: they are not reported together with it, unless the two conditions are unrelated.

  • R41.82 Altered mental status, unspecified
    altered level of consciousness (R40.-)

Use Additional Code 2

These codes say to use an additional code from the note, and R40 is one of the codes named.

  • T65.85 Toxic effect of medetomidine
    somnolence, stupor and coma (R40.-)
  • T67.0 Heatstroke and sunstroke
    coma and stupor (R40.-)

Patient EducationClinical

Coma

A coma is a deep state of unconsciousness. An individual in a coma is alive but unable to move or respond to his or her environment. Coma may occur as a complication of an underlying illness, or as a result of injuries, such as brain injury.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About R40Overview

What is the ICD-10 code for somnolence, stupor and coma?

R40 is the ICD-10-CM category for somnolence, stupor and coma, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is R40 (Somnolence, stupor and coma) a billable code?

No. This is a category header that groups the codes for somnolence, stupor and coma, and headers cannot be submitted on claims. Claims for somnolence, stupor and coma need a more specific code from this category, such as R40.0, R40.1, and R40.20.

Can R40 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the somnolence, stupor and coma is established, that condition takes the principal position instead.

Can R40 be reported with P91.5?

Not as a rule. The Excludes1 note on R40 lists "neonatal coma (P91.5)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).