ICD-10-CM 2027 diagnosis code
R41.82Altered mental status, unspecified
R41.82 is a valid, billable ICD-10-CM code for altered mental status, unspecified. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.
Looking up by condition? See ICD-10 code for Altered mental status.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About R41.82
R41.82 is the ICD-10-CM diagnosis code for Altered mental status, unspecified. It belongs to category R41 (other symptoms and signs involving cognitive functions and awareness), 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 billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
Within R41.8, choose R41.82 (Altered mental status, unspecified) only when documentation doesn't support a more specific option: age-related cognitive decline (R41.81), borderline intellectual functioning (R41.83), other specified cognitive deficit (R41.84), Anosognosia (R41.85) and other symptoms and signs involving cognitive functions and awareness (R41.89).
Don't report R41.82 together with the conditions in its Excludes1 note: altered level of consciousness (R40.-), altered mental status due to known condition - code to condition and delirium NOS (R41.0).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 947 (Signs and Symptoms with MCC, relative weight 1.261) and DRG 948 (Signs and Symptoms without MCC, relative weight 0.7835), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 780.97 (Altered mental status).
Coding notes
Notes that apply from higher levels
Instructions written at a parent level also apply to R41.82.
Broader instructions also apply from 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.
Alphabetic index entries
4 entriesTerms in the official ICD-10-CM index that lead to R41.82.
Codes whose notes reference R41.82
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 23 · Factors Influencing Health Status and Other Contacts with Health Services
ICD-9-CM equivalent
Converter →- 780.97Altered mental statusapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about R41.82
Is R41.82 billable?
- Yes. R41.82 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R41.82 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R41.82 as a principal diagnosis.
Is R41.82 a CC or MCC?
- No. R41.82 is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does R41.82 group to?
- R41.82 is used in the MS-DRG v44.0 logic for MS-DRG 947 (Signs and Symptoms with MCC) and MS-DRG 948 (Signs and Symptoms without MCC). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for R41.82?
- The CMS General Equivalence Mappings map R41.82 to ICD-9-CM 780.97.