2026 ICD-10-CM Diagnosis Code M00.9Pyogenic arthritis, unspecified

ICD-10-CM Codes›M00–M99›M00-M02›M00

ICD-10-CM M00.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

M00.9 is a billable ICD-10-CM diagnosis code for pyogenic arthritis, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 485 through 487, 548 through 550. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Bacterial infections and Infective arthritis.

Code Identity

ICD-10-CM Code
M00.9
Billable Status
Yes — Valid for Submission
Code Describes
Pyogenic arthritis, unspecified
Short Description
Pyogenic arthritis, unspecified
Same as the full description in the CMS dataset.
Parent Code
M00
Pyogenic arthritis

Code Classification

ChapterM00–M99Diseases of the musculoskeletal system and connective tissue
SectionM00-M02Infectious arthropathies
CategoryM00Pyogenic arthritis
This CodeM00.9Pyogenic arthritis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute bacterial arthritis
  • Acute infective arthritis
  • Acute infective polyarthritis
  • Acute polyarthritis
  • Acute suppurative arthritis
  • Acute suppurative arthritis caused by bacteria
  • Arthritis due to parasitic infection
  • Arthritis of lower limb due to parasitic infection
  • Arthritis of temporomandibular joint caused by internal joint prosthesis
  • Bilateral infective arthritis of hands
  • Bilateral infective arthritis of hips
  • Bilateral infective arthritis of knees
  • Bilateral infective arthritis of wrist regions
  • Chronic infective arthritis
  • Chronic infective polyarthritis
  • Cystic acne
  • Elbow pyogenic arthritis
  • Hidradenitis suppurativa pyoderma gangrenosum complex
  • Infectious arthritis of temporomandibular joint
  • Infectious arthritis of temporomandibular joint caused by internal joint prosthesis
  • Infectious disorder of joint
  • Infective arthritis
  • Infective arthritis co-occurrent with human immunodeficiency virus infection
  • Infective arthritis of ankle and/or foot
  • Infective arthritis of distal interphalangeal joint of finger
  • Infective arthritis of elbow
  • Infective arthritis of first metatarsophalangeal joint
  • Infective arthritis of hip
  • Infective arthritis of interphalangeal joint of toe
  • Infective arthritis of joint of bilateral shoulder regions
  • Infective arthritis of joint of hand
  • Infective arthritis of joint of left shoulder region
  • Infective arthritis of joint of right shoulder region
  • Infective arthritis of left ankle
  • Infective arthritis of left elbow
  • Infective arthritis of left foot
  • Infective arthritis of left glenohumeral joint
  • Infective arthritis of left hand
  • Infective arthritis of left hip
  • Infective arthritis of left knee
  • Infective arthritis of left wrist
  • Infective arthritis of metatarsophalangeal joint of lesser toe
  • Infective arthritis of pelvis
  • Infective arthritis of proximal interphalangeal joint of finger
  • Infective arthritis of right ankle
  • Infective arthritis of right elbow
  • Infective arthritis of right foot
  • Infective arthritis of right glenohumeral joint
  • Infective arthritis of right hand
  • Infective arthritis of right hip
  • Infective arthritis of right knee
  • Infective arthritis of right wrist
  • Infective arthritis of shoulder region
  • Infective arthritis of wrist
  • Infective arthritis with AIDS
  • Infective polyarthritis
  • Inflammation of interphalangeal joint of toe
  • Knee pyogenic arthritis
  • PAPASH syndrome
  • Polyarticular viral arthritis
  • Pyogenic arthritis of foot
  • Pyogenic arthritis of hip
  • Pyogenic arthritis of multiple sites
  • Pyogenic arthritis of pelvic region
  • Pyogenic arthritis of shoulder region
  • Pyogenic arthritis of the ankle and/or foot
  • Pyogenic arthritis of the pelvic region and thigh
  • Pyogenic arthritis, pyoderma gangrenosum, acne syndrome
  • Subacute arthritis
  • Subacute arthropathy
  • Subacute infective arthritis
  • Subacute infective polyarthritis
  • Suppurative arthritis
  • Suppurative arthritis caused by bacteria
  • Viral arthritis
  • Wrist pyogenic arthritis

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Infective arthritis NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Abscess(connective tissue) (embolic) (fistulous) (infective) (metastatic) (multiple) (pernicious) (pyogenic) (septic)
      • knee
        • joint
    • Arthritis, arthritic(acute) (chronic) (nonpyogenic) (subacute)
      • pyogenic or pyemic (any site except spine)
    • Disease, diseased
      • hip (joint)
        • suppurative
    • Infection, infected, infective(opportunistic)
      • acromioclavicular
    • Infection, infected, infective(opportunistic)
      • hip (joint) NEC
    • Infection, infected, infective(opportunistic)
      • joint NEC
    • Infection, infected, infective(opportunistic)
      • knee (joint) NEC
    • Infection, infected, infective(opportunistic)
      • knee (joint) NEC
        • joint
    • Infection, infected, infective(opportunistic)
      • metatarsophalangeal
    • Infection, infected, infective(opportunistic)
      • shoulder (joint) NEC

Clinical ClassificationClinical

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

CCSR INF003
Bacterial infections
Default principal diagnosis: inpatient No · outpatient No
CCSR MUS001
Infective arthritis
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Infectious Arthritis

Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Infectious arthritis is an infection in the joint. The infection comes from a bacterial, viral, or fungal infection that spreads from another part of the body. Symptoms of infectious arthritis include:

Read the full article at MedlinePlus

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

Convert M00.9 to ICD-9-CMHistory

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

ICD-9-CM
711.00 Pyogen arthritis-unspec
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 M00.9Overview

Is M00.9 (Pyogenic arthritis) a billable code?

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

What MS-DRG does M00.9 group to?

When pyogenic arthritis, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 485, 486, 487, 548, 549, 550, with relative weights from 0.8741 to 3.2271 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of M00.9?

Under the General Equivalence Mappings, pyogenic arthritis, unspecified converts to ICD-9-CM 711.00 (pyogen arthritis-unspec). 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.