2026 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 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

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

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • 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

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 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About R40Overview

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.