2026 ICD-10-CM Diagnosis Code R41.82Altered mental status, unspecified

ICD-10-CM CodesR00–R99R40-R46R41

ICD-10-CM R41.82
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

R41.82 is a billable ICD-10-CM diagnosis code for altered mental status, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 947 through 948. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Nervous system signs and symptoms.

Code Identity

ICD-10-CM Code
R41.82
Billable Status
Yes — Valid for Submission
Code Describes
Altered mental status, unspecified
Short Description
Altered mental status, unspecified
Same as the full description in the CMS dataset.
Parent Code
Other symptoms and signs involving cognitive functions and awareness

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
CategoryR41Other symptoms and signs involving cognitive functions and awareness
This CodeR41.82Altered mental status, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Altered mental status
  • Character trait finding of level of suggestibility
  • Disturbance in suggestibility
  • Disturbance of consciousness
  • Drugged state
  • Grayout
  • Hypnotic state
  • Mental health impairment
  • Narcosis
  • Sedated
  • Semiconscious
  • Transient altered mental status
  • Vacant episode
  • Whiteout

Tabular List NotesGuidance

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

Inclusion Terms

  • Change in mental status NOS

Type 1 Excludes

  • altered level of consciousness R40
  • altered mental status due to known condition - code to condition
  • delirium NOS R41.0

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Alteration(of), Altered
      • mental status
    • Change(s) (in) (of)
      • mental status
    • Symptoms NEC
      • involving
        • awareness
          • altered mental status
    • Symptoms NEC
      • involving
        • cognitive functions
          • altered mental status

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR SYM010
Nervous system signs and symptoms
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Mental Disorders

Mental disorders (or mental illnesses) are conditions that affect your thinking, feeling, mood, and behavior. They may happen over a short period of time or come and go. Some can be chronic (long-lasting). They can affect your ability to relate to others and function each day..

The full article covers:

  • What are mental disorders?
  • What are some types of mental disorders?
  • What causes mental disorders?
  • Who is at risk for mental disorders?
  • How are mental disorders diagnosed?
  • What are the treatments for mental disorders?

Read the full article at MedlinePlus

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

Convert R41.82 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
780.97 Altered mental status
Approximate The match is approximate rather than exact.

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 R41.82Overview

Is R41.82 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report altered mental status, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does R41.82 group to?

When altered mental status, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 947, 948, with relative weights from 0.8005 to 1.2694 depending on complications. Higher weights mean higher Medicare reimbursement.

Can R41.82 be a principal diagnosis?

Use it with care. This is a symptom code, so once a definitive diagnosis explaining the altered mental status, unspecified is established, that condition takes the principal position instead.

What is the ICD-9 equivalent of R41.82?

Under the General Equivalence Mappings, altered mental status, unspecified converts to ICD-9-CM 780.97 (altered mental status). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.