M00.149 ICD-10-CM Code: Pneumococcal arthritis, unspecified hand

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for M00.149 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 M00.149 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for M00.149

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

Before you code M00.149

1. Unspecified does not mean incorrect. When the record gives no greater specificity, M00.149 may be the appropriate code. Check the record for detail that supports a more specific sibling. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

   ReviewM00.141, M00.142

   See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

2. Laterality is coded in this family. Confirm the side documented — right, left, or bilateral — and select the matching code (this page’s code: unspecified). The unspecified-side code applies only when the record states no side. Laterality is assigned from the documented side; where a bilateral code exists and both sides are documented, it is used instead of two unilateral codes (Guidelines I.B.13).

   ReviewM00.141 · right, M00.142 · left

   Guide: Laterality coding →

Choose the right path

1. Does the record document the detail a more specific sibling code needs?
   Yes → Review the specific siblings in this subcategory.
   No → Continue — M00.149 is appropriate when the documentation goes no further.

   ReviewM00.141, M00.142

2. Is the side documented?
   Yes → Select the code for the documented side (or the bilateral code when both sides are documented and one exists).
   No → Use the unspecified-side code only when the record states no side; a query is the alternative.

   ReviewM00.141 · right, M00.142 · left

Consider M00.149. Then confirm the code is valid for the date of service in the Verify section.

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).

Laterality

Right, left or bilateral as documented; unspecified only when the record states no side (Guidelines I.B.13).

Any detail beyond this code’s title

What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

• Excludes2 — not part of M00.149(1 note)

  Coding workflow: The conditions named in this note are not included in M00.149. 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

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.

Don’t confuse M00.149 with…

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

The codes most likely to be picked instead of M00.149 — 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.

• M00.141— Laterality relationship (Review)

  Same condition; these differ only in which side is documented.

  The same condition on the other side; the documented side decides, and a bilateral code, where one exists, replaces the pair when both sides are documented.

  What moves you there: A documented right side moves the case to M00.141.

  Full comparison: M00.149 vs M00.141 →

• M00.142— Laterality relationship (Review)

  Same condition; these differ only in which side is documented.

  The same condition on the other side; the documented side decides, and a bilateral code, where one exists, replaces the pair when both sides are documented.

  What moves you there: A documented left side moves the case to M00.142.

  Full comparison: M00.149 vs M00.142 →

• 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: M00.149 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 460 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 condition, opposite side

Same category and title, differing only in which side of the body is affected.

M00.141 — Pneumococcal arthritis, right hand (right)Compare M00.149 vs M00.141 →, M00.142 — Pneumococcal arthritis, left hand (left)Compare M00.149 vs M00.142 →

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.

M00.112 — 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, M00.141 — Pneumococcal arthritis, right hand, M00.142 — Pneumococcal arthritis, left hand, M00.151 — Pneumococcal arthritis, right hip, M00.152 — Pneumococcal arthritis, left hip, M00.159 — Pneumococcal arthritis, unspecified hip, M00.161 — Pneumococcal arthritis, right knee, M00.162 — Pneumococcal arthritis, left knee, M00.169 — Pneumococcal arthritis, unspecified knee, M00.171 — Pneumococcal arthritis, right ankle and foot, M00.172 — Pneumococcal arthritis, left ankle and foot, M00.179 — Pneumococcal arthritis, unspecified ankle and foot, M00.18 — Pneumococcal arthritis, vertebrae, +588 more

Same clinical category (CCSR)

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

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, M00.141 — Pneumococcal arthritis, right hand, M00.142 — Pneumococcal arthritis, left hand, M00.151 — Pneumococcal arthritis, right hip, M00.152 — Pneumococcal arthritis, left hip, M00.159 — Pneumococcal arthritis, unspecified hip, M00.161 — Pneumococcal arthritis, right knee, M00.162 — Pneumococcal arthritis, left knee, M00.169 — Pneumococcal arthritis, unspecified knee, M00.171 — Pneumococcal arthritis, right ankle and foot, M00.172 — Pneumococcal arthritis, left ankle and foot, M00.179 — Pneumococcal arthritis, unspecified ankle and foot, M00.18 — Pneumococcal arthritis, vertebrae, +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 M00.149 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

Nearest codes (40)

• M00 — Pyogenic arthritis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.079 — Staphylococcal arthritis, unspecified ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.08 — Staphylococcal arthritis, vertebrae[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.09 — Staphylococcal polyarthritis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.1 — Pneumococcal arthritis and polyarthritis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.10 — Pneumococcal arthritis, unspecified joint[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.11 — Pneumococcal arthritis, shoulder[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• M00.111 — Pneumococcal arthritis, right shoulder[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 M00.149 in its code family, with their registry titles.

• M00.132 — Pneumococcal arthritis, left wrist
• M00.139 — Pneumococcal arthritis, unspecified wrist
• M00.14 — Pneumococcal arthritis, hand
• M00.141 — Pneumococcal arthritis, right hand
• M00.142 — Pneumococcal arthritis, left hand
• M00.15 — Pneumococcal arthritis, hip
• M00.151 — Pneumococcal arthritis, right hip
• M00.152 — Pneumococcal arthritis, left hip
• M00.159 — Pneumococcal arthritis, unspecified hip
• M00.16 — Pneumococcal arthritis, knee

View all codes in the M00 family