2026 ICD-10-CM Diagnosis Code M65.231Calcific tendinitis, right forearm

ICD-10-CM Codes›M00–M99›M65-M67›M65

ICD-10-CM M65.231
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M65.231 is a billable ICD-10-CM diagnosis code for calcific tendinitis, right 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Tendon and synovial disorders.

Code Identity

ICD-10-CM Code
M65.231
Billable Status
Yes — Valid for Submission
Code Describes
Calcific tendinitis, right forearm
Short Description
Calcific tendinitis, right forearm
Same as the full description in the CMS dataset.
Parent Code
M65.23
Calcific tendinitis, forearm

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM65-M67Disorders of synovium and tendon
CategoryM65Synovitis and tenosynovitis
This CodeM65.231Calcific tendinitis, right forearm

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral calcific tendinitis of wrists
  • Calcific tendinitis of bilateral forearms
  • Calcific tendinitis of left forearm
  • Calcific tendinitis of left wrist
  • Calcific tendinitis of right forearm
  • Calcific tendinitis of right wrist
  • Calcific tendinitis of wrist region
  • Tendinitis of left wrist region
  • Tendinitis of right wrist region
  • Tendinitis of wrist
  • Tendonitis of bilateral wrists

Clinical ClassificationClinical

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

CCSR MUS009
Tendon and synovial disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Tendinitis

Tendons are flexible bands of tissue that connect muscles to bones. They help your muscles move your bones. Tendinitis is the severe swelling of a tendon.

Read the full article at MedlinePlus

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

Convert M65.231 to ICD-9-CMHistory

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

ICD-9-CM
727.82 Calcium deposit tendon
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 M65.231Overview

Is M65.231 (Calcific tendinitis, forearm) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report calcific tendinitis, right forearm on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does M65.231 group to?

When calcific tendinitis, right 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 M65.231?

Under the General Equivalence Mappings, calcific tendinitis, right forearm converts to ICD-9-CM 727.82 (calcium deposit tendon). 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.