2026 ICD-10-CM Diagnosis Code M21.941Unspecified acquired deformity of hand, right hand

ICD-10-CM Codes›M00–M99›M20-M25›M21

ICD-10-CM M21.941
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M21.941 is a billable ICD-10-CM diagnosis code for unspecified acquired deformity of hand, right hand. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 564 through 566. Coders also document this condition as acquired deformity of right hand. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acquired deformities (excluding foot).

Code Identity

ICD-10-CM Code
M21.941
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified acquired deformity of hand, right hand
Short Description
Unspecified acquired deformity of hand, right hand
Same as the full description in the CMS dataset.
Parent Code
M21.94
Unspecified acquired deformity of hand

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM20-M25Other joint disorders
CategoryM21Other acquired deformities of limbs
This CodeM21.941Unspecified acquired deformity of hand, right hand

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acquired deformity of right hand
  • Bilateral acquired deformity of hands
  • Bilateral deformity of hands due to rheumatoid arthritis
  • Deformity of hand due to rheumatoid arthritis
  • Deformity of right hand co-occurrent and due to rheumatoid arthritis

Clinical ClassificationClinical

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

CCSR MUS023
Acquired deformities (excluding foot)
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Hand Injuries and Disorders

No matter how old you are or what you do for a living, you are always using your hands. When there is something wrong with them, you may not be able to do your regular activities.

Read the full article at MedlinePlus

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

Convert M21.941 to ICD-9-CMHistory

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

ICD-9-CM
736.00 Forearm deformity NOS
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 M21.941Overview

Is M21.941 (Unspecified acquired deformity of hand) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified acquired deformity of hand, right hand on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M21.941 group to?

When unspecified acquired deformity of hand, right hand is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 565, 566, with relative weights from 0.7493 to 1.5436 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M21.941?

Under the General Equivalence Mappings, unspecified acquired deformity of hand, right hand converts to ICD-9-CM 736.00 (forearm deformity NOS). 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.