2026 ICD-10-CM Diagnosis Code M77.12Lateral epicondylitis, left elbow

ICD-10-CM Codes›M00–M99›M70-M79›M77

ICD-10-CM M77.12
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M77.12 is a billable ICD-10-CM diagnosis code for lateral epicondylitis, left elbow. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified connective tissue disease.

Code Identity

ICD-10-CM Code
M77.12
Billable Status
Yes — Valid for Submission
Code Describes
Lateral epicondylitis, left elbow
Short Description
Lateral epicondylitis, left elbow
Same as the full description in the CMS dataset.
Parent Code
M77.1
Lateral epicondylitis

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM70-M79Other soft tissue disorders
CategoryM77Other enthesopathies
This CodeM77.12Lateral epicondylitis, left elbow

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral lateral elbow tendinopathy
  • Disorder of enthesis of bilateral elbow regions
  • Elbow tendinopathy
  • Enthesopathy of left elbow
  • Enthesopathy of right elbow
  • Lateral epicondylitis
  • Left lateral elbow tendinopathy
  • Right lateral elbow tendinopathy

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

Clinical InformationClinical

  • Elbow Tendinopathy

    inflammation (tendinitis) or degeneration (tendinosis) of the tendons of the elbow.

  • Lateral Epicondylitis Assessment|Tennis elbow test

    physical manipulation methods used to assess for pain over the lateral epicondyle.

  • Lateral Epicondylitis

    inflammation of the lateral epicondyle.

  • Epicondylitis

    inflammation of the epicondyles.

Patient EducationClinical

Elbow Injuries and Disorders

Your elbow joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the elbow joint move. When any of these structures is hurt or diseased, you have elbow problems.

Read the full article at MedlinePlus

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

Convert M77.12 to ICD-9-CMHistory

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

ICD-9-CM
726.32 Lateral epicondylitis
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 M77.12Overview

Is M77.12 (Lateral epicondylitis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report lateral epicondylitis, left elbow on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M77.12 group to?

When lateral epicondylitis, left elbow 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 M77.12?

Under the General Equivalence Mappings, lateral epicondylitis, left elbow converts to ICD-9-CM 726.32 (lateral epicondylitis). 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.