2026 ICD-10-CM Diagnosis Code M86.8X9Other osteomyelitis, unspecified sites

ICD-10-CM Codes›M00–M99›M86-M90›M86

ICD-10-CM M86.8X9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M86.8X9 is a billable ICD-10-CM diagnosis code for other osteomyelitis, unspecified sites. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 456 through 458, 539 through 541. The code is flagged as an unspecified code, since codes identifying laterality exist in the same family. Coders also document this condition as Brodie's abscess. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Osteomyelitis.

Code Identity

ICD-10-CM Code
M86.8X9
Billable Status
Yes — Valid for Submission
Code Describes
Other osteomyelitis, unspecified sites
Short Description
Other osteomyelitis, unspecified sites
Same as the full description in the CMS dataset.
Parent Code
M86.8X
Other osteomyelitis

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM86-M90Other osteopathies
CategoryM86Osteomyelitis
This CodeM86.8X9Other osteomyelitis, unspecified sites

Code EditsBilling

Medicare Code Editor checks that affect claim validity for M86.8X9.

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.

  • Brodie's abscess
  • Chronic sclerosing nonsuppurative osteomyelitis
  • Diaphysitis
  • Diffuse sclerosing osteomyelitis
  • Florid reactive periostitis
  • Osteomyelitis due to type 2 diabetes mellitus
  • Posttraumatic periosteoma
  • Rheumatoid osteoperiostitis
  • Sclerosing osteomyelitis

Clinical ClassificationClinical

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

CCSR MUS002
Osteomyelitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Osteomyelitis

    inflammation of the bone as a result of infection. it may be caused by a variety of infectious agents, especially pyogenic (pus - producing) bacteria.

Patient EducationClinical

Bone Infections

Like other parts of the body, bones can get infected. The infections are usually bacterial, but can also be fungal. They may spread to the bone from nearby skin or muscles, or from another part of the body through the bloodstream.

Read the full article at MedlinePlus

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

Convert M86.8X9 to ICD-9-CMHistory

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

ICD-9-CM
730.10 Chr osteomyelitis-unsp
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 M86.8X9Overview

Is M86.8X9 (Other osteomyelitis) a billable code?

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

What MS-DRG does M86.8X9 group to?

When other osteomyelitis, unspecified sites is the principal diagnosis on an inpatient stay, it groups to MS-DRG 456, 457, 458, 539, 540, 541, with relative weights from 0.7715 to 8.4034 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M86.8X9?

Under the General Equivalence Mappings, other osteomyelitis, unspecified sites converts to ICD-9-CM 730.10 (chr osteomyelitis-unsp). 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.