2026 ICD-10-CM Diagnosis Code M79.A12Nontraumatic compartment syndrome of left upper extremity

ICD-10-CM Codes›M00–M99›M70-M79›M79

ICD-10-CM M79.A12
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M79.A12 is a billable ICD-10-CM diagnosis code for nontraumatic compartment syndrome of left upper 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. Coders also document this condition as nontraumatic compartment syndrome of bilateral upper limbs. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified connective tissue disease.

Code Identity

ICD-10-CM Code
M79.A12
Billable Status
Yes — Valid for Submission
Code Describes
Nontraumatic compartment syndrome of left upper extremity
Short Description
Nontraumatic compartment syndrome of left upper extremity
Same as the full description in the CMS dataset.
Parent Code
M79.A1
Nontraumatic compartment syndrome of upper 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.A12Nontraumatic compartment syndrome of left upper extremity

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Nontraumatic compartment syndrome of bilateral upper limbs
  • Nontraumatic compartment syndrome of left upper limb
  • Nontraumatic compartment syndrome of right upper limb
  • Nontraumatic compartment syndrome of upper 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

Patient EducationClinical

Arm Injuries and Disorders

Of the 206 bones in your body, three of them are in your arm: the humerus, radius, and ulna. Your arms are also made up of muscles, joints, tendons, and other connective tissue. Injuries to any of these parts of the arm can occur during sports, a fall, or an accident.

Read the full article at MedlinePlus

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

Convert M79.A12 to ICD-9-CMHistory

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

ICD-9-CM
729.71 Nontraum comp syn-up ext
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.A12Overview

Is M79.A12 (Nontraumatic compartment syndrome of upper extremity) a billable code?

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

What MS-DRG does M79.A12 group to?

When nontraumatic compartment syndrome of left upper 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.A12?

Under the General Equivalence Mappings, nontraumatic compartment syndrome of left upper extremity converts to ICD-9-CM 729.71 (nontraum comp syn-up ext). 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.