2026 ICD-10-CM Diagnosis Code M62.539Muscle wasting and atrophy, not elsewhere classified, unspecified forearm

ICD-10-CM Codes›M00–M99›M60-M63›M62

ICD-10-CM M62.539
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M62.539 is a billable ICD-10-CM diagnosis code for muscle wasting and atrophy, not elsewhere classified, unspecified forearm. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 557 through 558. Coders also document this condition as atrophy of muscle of forearm. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Muscle disorders.

Code Identity

ICD-10-CM Code
M62.539
Billable Status
Yes — Valid for Submission
Code Describes
Muscle wasting and atrophy, not elsewhere classified, unspecified forearm
Short Description
Muscle wasting and atrophy, NEC, unsp forearm
Parent Code
M62.53
Muscle wasting and atrophy, not elsewhere classified, forearm

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM60-M63Disorders of muscles
CategoryM62Other disorders of muscle
This CodeM62.539Muscle wasting and atrophy, not elsewhere classified, unspecified forearm

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Atrophy of muscle of forearm
  • Atrophy of muscle of lower leg
  • Atrophy of muscle of lower leg and forearm

Clinical ClassificationClinical

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

CCSR MUS026
Muscle disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Muscle Disorders

Your muscles help you move and help your body work. Different types of muscles have different jobs. There are many problems that can affect muscles. Muscle disorders can cause weakness, pain or even paralysis.

Read the full article at MedlinePlus

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

Convert M62.539 to ICD-9-CMHistory

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

ICD-9-CM
728.2 Musc disuse atrophy NEC
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 M62.539Overview

Is M62.539 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report muscle wasting and atrophy, not elsewhere classified, unspecified forearm on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M62.539 group to?

When muscle wasting and atrophy, not elsewhere classified, unspecified forearm is the principal diagnosis on an inpatient stay, it groups to MS-DRG 557, 558, with relative weights from 0.8932 to 1.4869 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M62.539?

Under the General Equivalence Mappings, muscle wasting and atrophy, not elsewhere classified, unspecified forearm converts to ICD-9-CM 728.2 (musc disuse atrophy NEC). 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.