2026 ICD-10-CM Diagnosis Code M79.A29Nontraumatic compartment syndrome of unspecified lower extremity

ICD-10-CM Codes›M00–M99›M70-M79›M79

ICD-10-CM M79.A29
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M79.A29 is a billable ICD-10-CM diagnosis code for nontraumatic compartment syndrome of unspecified lower extremity. 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. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as nontraumatic compartment syndrome of lower limb. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified connective tissue disease.

Code Identity

ICD-10-CM Code
M79.A29
Billable Status
Yes — Valid for Submission
Code Describes
Nontraumatic compartment syndrome of unspecified lower extremity
Short Description
Nontraumatic compartment syndrome of unsp lower extremity
Parent Code
M79.A2
Nontraumatic compartment syndrome of lower extremity

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.A29Nontraumatic compartment syndrome of unspecified lower extremity

Code EditsBilling

Medicare Code Editor checks that affect claim validity for M79.A29.

Unspecified codes
Unspecified codes exist in the ICD-10-CM classification for circumstances when documentation in the medical record does not provide the level of detail needed to support reporting a more specific code. However, in the inpatient setting, there should generally be very limited and rare circumstances for which the laterality (right, left, bilateral) of a condition is unable to be documented and reported. The following pages contain the list of unspecified ICD-10-CM diagnosis codes for which there is a more specific code to identify laterality (right, left, bilateral) within that code family.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Nontraumatic compartment syndrome of lower limb

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

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Convert M79.A29 to ICD-9-CMHistory

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

ICD-9-CM
729.72 Nontraum comp syn-low ex
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 M79.A29Overview

Is M79.A29 (Nontraumatic compartment syndrome of lower extremity) a billable code?

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

What MS-DRG does M79.A29 group to?

When nontraumatic compartment syndrome of unspecified lower extremity 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.A29?

Under the General Equivalence Mappings, nontraumatic compartment syndrome of unspecified lower extremity converts to ICD-9-CM 729.72 (nontraum comp syn-low ex). 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.