M00.09 ICD-10-CM Code: Staphylococcal polyarthritis

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for M00.09 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on M00.09 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for M00.09

MedCoder structured workflow — derived from this code’s own official record

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

The conditions the Use Additional Code note names

Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.

Official instructions as workflow

• Excludes2 — not part of M00.09(1 note)

  Coding workflow: The conditions named in this note are not included in M00.09. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareT84.5

  See the official tabular notes · Guidelines I.A.12.b

• Use Additional Code — after identifying M00.09(1 note)

  Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with M00.09 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

  See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Indexed Clinical Terms (1)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute), staphylococcal, multiple site

Don’t confuse M00.09 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of M00.09 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• T84.5— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of infection and inflammatory reaction due to internal joint prosthesis adds T84.5; it is not part of this code and both may be reported when both are documented.

  Full comparison: M00.09 vs T84.5 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 938 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 548 (MDC 08), DRG 549 (MDC 08), DRG 550 (MDC 08).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):MUS001 — Infective arthritis (default); INF003 — Bacterial infections.

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis) for risk-adjusted payment.

M00.051 — Staphylococcal arthritis, right hip, M00.052 — Staphylococcal arthritis, left hip, M00.059 — Staphylococcal arthritis, unspecified hip, M00.061 — Staphylococcal arthritis, right knee, M00.062 — Staphylococcal arthritis, left knee, M00.069 — Staphylococcal arthritis, unspecified knee, M00.071 — Staphylococcal arthritis, right ankle and foot, M00.072 — Staphylococcal arthritis, left ankle and foot, M00.079 — Staphylococcal arthritis, unspecified ankle and foot, M00.08 — Staphylococcal arthritis, vertebrae, M00.10 — Pneumococcal arthritis, unspecified joint, M00.111 — Pneumococcal arthritis, right shoulder, M00.112 — Pneumococcal arthritis, left shoulder, M00.119 — Pneumococcal arthritis, unspecified shoulder, M00.121 — Pneumococcal arthritis, right elbow, M00.122 — Pneumococcal arthritis, left elbow, M00.129 — Pneumococcal arthritis, unspecified elbow, M00.131 — Pneumococcal arthritis, right wrist, M00.132 — Pneumococcal arthritis, left wrist, M00.139 — Pneumococcal arthritis, unspecified wrist, +588 more

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical categories (Infective arthritis, Bacterial infections).

M00.051 — Staphylococcal arthritis, right hip, M00.052 — Staphylococcal arthritis, left hip, M00.059 — Staphylococcal arthritis, unspecified hip, M00.061 — Staphylococcal arthritis, right knee, M00.062 — Staphylococcal arthritis, left knee, M00.069 — Staphylococcal arthritis, unspecified knee, M00.071 — Staphylococcal arthritis, right ankle and foot, M00.072 — Staphylococcal arthritis, left ankle and foot, M00.079 — Staphylococcal arthritis, unspecified ankle and foot, M00.08 — Staphylococcal arthritis, vertebrae, M00.10 — Pneumococcal arthritis, unspecified joint, M00.111 — Pneumococcal arthritis, right shoulder, M00.112 — Pneumococcal arthritis, left shoulder, M00.119 — Pneumococcal arthritis, unspecified shoulder, M00.121 — Pneumococcal arthritis, right elbow, M00.122 — Pneumococcal arthritis, left elbow, M00.129 — Pneumococcal arthritis, unspecified elbow, M00.131 — Pneumococcal arthritis, right wrist, M00.132 — Pneumococcal arthritis, left wrist, M00.139 — Pneumococcal arthritis, unspecified wrist, +411 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Arthritis, arthritic”; these codes share that main term but sit in a different category of the Tabular List.

E85.4 — Organ-limited amyloidosis (in, amyloidosis), E88.9 — Metabolic disorder, unspecified (in, metabolic disorder NEC), G95.0 — Syringomyelia and syringobulbia (in, syringomyelia), G98.0 — Neurogenic arthritis, not elsewhere classified (in, neurological disorder NEC), J98.9 — Respiratory disorder, unspecified (in, respiratory disorder NEC), L40.50 — Arthropathic psoriasis, unspecified (psoriatic), L40.52 — Psoriatic arthritis mutilans (mutilans), L40.54 — Psoriatic juvenile arthropathy (juvenile, psoriatic), L51.9 — Erythema multiforme, unspecified (in, erythema, multiforme), L52 — Erythema nodosum (in, erythema, nodosum), M04.1 — Periodic fever syndromes (in, Mediterranean fever, familial), M05.70 — Rheumatoid arthritis with rheumatoid factor of unspecified site without organ or systems involvement (rheumatoid, seropositive, without organ involvement), M05.71 — Rheumatoid arthritis with rheumatoid factor of shoulder without organ or systems involvement (rheumatoid, seropositive, without organ involvement, shoulder), M05.72 — Rheumatoid arthritis with rheumatoid factor of elbow without organ or systems involvement (rheumatoid, seropositive, without organ involvement, elbow), M05.73 — Rheumatoid arthritis with rheumatoid factor of wrist without organ or systems involvement (rheumatoid, seropositive, without organ involvement, wrist), M05.74 — Rheumatoid arthritis with rheumatoid factor of hand without organ or systems involvement (rheumatoid, seropositive, without organ involvement, hand joint), M05.75 — Rheumatoid arthritis with rheumatoid factor of hip without organ or systems involvement (rheumatoid, seropositive, without organ involvement, hip), M05.76 — Rheumatoid arthritis with rheumatoid factor of knee without organ or systems involvement (rheumatoid, seropositive, without organ involvement, knee), M05.77 — Rheumatoid arthritis with rheumatoid factor of ankle and foot without organ or systems involvement (rheumatoid, seropositive, without organ involvement, ankle), M05.79 — Rheumatoid arthritis with rheumatoid factor of multiple sites without organ or systems involvement (rheumatoid, seropositive, without organ involvement, multiple sites), +153 more

Contextual Map

Every relationship of M00.09 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

• M00-M99 — Chapter 13: Diseases of the Musculoskeletal System and Connective Tissue (M00-M99) (M00-M99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00-M25 — Arthropathies[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00-M02 — Infectious arthropathies[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Clinical classification (CCSR)

• MUS001 — Infective arthritis[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)
• INF003 — Bacterial infections[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 92 — Bone/Joint/Muscle/Severe Soft Tissue Infections/Necrosis [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 548 — SEPTIC ARTHRITIS WITH MCC[MS-DRG]: “SEPTIC ARTHRITIS WITH MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 549 — SEPTIC ARTHRITIS WITH CC[MS-DRG]: “SEPTIC ARTHRITIS WITH CC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 550 — SEPTIC ARTHRITIS WITHOUT CC/MCC[MS-DRG]: “SEPTIC ARTHRITIS WITHOUT CC/MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 08 — Diseases and Disorders of the Musculoskeletal System and Connective Tissue[MDC crossing]: “Diseases and Disorders of the Musculoskeletal System and Connective Tissue — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 18,508 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Arthritis, arthritic (acute) (chronic) (nonpyogenic) (subacute), staphylococcal, multiple site[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (40)

• M00 — Pyogenic arthritis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.031 — Staphylococcal arthritis, right wrist[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.032 — Staphylococcal arthritis, left wrist[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.039 — Staphylococcal arthritis, unspecified wrist[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.04 — Staphylococcal arthritis, hand[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.041 — Staphylococcal arthritis, right hand[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.042 — Staphylococcal arthritis, left hand[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.049 — Staphylococcal arthritis, unspecified hand[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 32 more

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Risk adjustment Official source data

2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M00.09 in its code family, with their registry titles.

• M00.07 — Staphylococcal arthritis, ankle and foot
• M00.071 — Staphylococcal arthritis, right ankle and foot
• M00.072 — Staphylococcal arthritis, left ankle and foot
• M00.079 — Staphylococcal arthritis, unspecified ankle and foot
• M00.08 — Staphylococcal arthritis, vertebrae
• M00.1 — Pneumococcal arthritis and polyarthritis
• M00.10 — Pneumococcal arthritis, unspecified joint
• M00.11 — Pneumococcal arthritis, shoulder
• M00.111 — Pneumococcal arthritis, right shoulder
• M00.112 — Pneumococcal arthritis, left shoulder

View all codes in the M00 family