2026 ICD-10-CM Diagnosis Code M79.A9Nontraumatic compartment syndrome of other sites

ICD-10-CM Codes›M00–M99›M70-M79›M79

ICD-10-CM M79.A9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M79.A9 is a billable ICD-10-CM diagnosis code for nontraumatic compartment syndrome of other sites. 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 nontraumatic exertional compartment syndrome. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified connective tissue disease.

Code Identity

ICD-10-CM Code
M79.A9
Billable Status
Yes — Valid for Submission
Code Describes
Nontraumatic compartment syndrome of other sites
Short Description
Nontraumatic compartment syndrome of other sites
Same as the full description in the CMS dataset.
Parent Code
M79.A
Nontraumatic compartment syndrome

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM70-M79Other soft tissue disorders
CategoryM79Other and unspecified soft tissue disorders, not elsewhere classified
This CodeM79.A9Nontraumatic compartment syndrome of other sites

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Nontraumatic exertional compartment syndrome

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.

    • Compartment syndrome(deep) (posterior) (traumatic)
      • nontraumatic
        • specified site NEC
    • Syndrome
      • compartment (deep) (posterior) (traumatic)
        • nontraumatic
          • specified site NEC

Clinical ClassificationClinical

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

CCSR MUS025
Other specified connective tissue disease
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 M79.A9 to ICD-9-CMHistory

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

ICD-9-CM
729.79 Nontrauma comp syn NEC
Exact Match The mapping is direct, with no qualifiers.

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 M79.A9Overview

Is M79.A9 (Nontraumatic compartment syndrome) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report nontraumatic compartment syndrome of other sites on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M79.A9 group to?

When nontraumatic compartment syndrome of other sites 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 M79.A9?

Under the General Equivalence Mappings, nontraumatic compartment syndrome of other sites converts to ICD-9-CM 729.79 (nontrauma comp syn NEC). The mapping is a direct match.

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.