Name: Juvenile arthritis, unspecified, multiple sites
Creator: MedCoder.ai

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives: 5 Excludes1 · 3 code-also instructions
Risk adjustment: CMS-HCC V28: 1 category · CMS-HCC V22 category 40 · RxHCC V08 category 83

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

MS-DRG 545 — CONNECTIVE TISSUE DISORDERS WITH MCC (MDC 08)
MS-DRG 546 — CONNECTIVE TISSUE DISORDERS WITH CC (MDC 08)
MS-DRG 547 — CONNECTIVE TISSUE DISORDERS WITHOUT CC/MCC (MDC 08)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Risk Adjustment (CMS-HCC)

Payment categories this diagnosis maps to under CMS-HCC V28, payment year 2026.

HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders (supersedes HCC 94)

Other models: CMS-HCC V22 HCC 40 · RxHCC V08 HCC 83

Risk scores depend on the enrollee's full accepted diagnosis set and segment; a category mapping alone does not determine payment.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for M08.99 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 M08.99 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

juvenile rheumatoid arthritis, unspecified (M08.0-) inherited from M08.9Compare M08.99 vs M08.0 →
arthropathy in Whipple's disease (M14.8) inherited from M08Compare M08.99 vs M14.8 →
Felty's syndrome (M05.0) inherited from M08Compare M08.99 vs M05.0 →
juvenile dermatomyositis (M33.0-) inherited from M08Compare M08.99 vs M33.0 →
psoriatic juvenile arthropathy (L40.54) inherited from M08Compare M08.99 vs L40.54 →

Code Also

Additional codes that may be required to fully describe the encounter.

any associated underlying condition, such as:
regional enteritis Crohn's disease
ulcerative colitis (K51.-) inherited from M08

Coder workflow for M08.99

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

Before you code M08.99

Unspecified does not mean incorrect. When the record gives no greater specificity, M08.99 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).
See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →
Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with M08.99. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).
See the official tabular notes

Choose the right path

Does the record document the detail a more specific sibling code needs?
Yes → Review the specific siblings in this subcategory.
No → Continue — M08.99 is appropriate when the documentation goes no further.
Does the documentation support a condition named in M08.99’s Excludes1 note?
Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
No → Continue.
ReviewM08.0, M14.8, M05.0, M33.0, L40.54

Consider M08.99. Then review the Code Also note, and 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).
Anatomical site: At the most specific level the record states; a site the classification separates cannot be assumed from a procedure or a measurement.
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

Excludes1 — check before selecting M08.99(5 notes)
Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with M08.99: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.
CompareM08.0, M14.8, M05.0, M33.0, L40.54
See the official tabular notes · Guidelines I.A.12.a
Code Also — related condition(3 notes)
Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.
ReviewK51
See the official tabular notes · Guidelines I.A.17

Coding decision scenarios

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

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the subcategory for a sibling that names the missing detail.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

Documentation: Both the condition M08.99 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewM08.0, M14.8, M05.0, M33.0, L40.54

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.

Code Overview

Juvenile arthritis, unspecified, multiple sites is a billable ICD-10-CM diagnosis code (M08.99).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

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), juvenile, multiple site

Don’t confuse M08.99 with…

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

The codes most likely to be picked instead of M08.99 — 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.

M08.0— Excludes1 conflict (Excludes1 — generally not reported together)
Not coded here — the tabular list excludes this pair for the same encounter.
Not reported together with this code, except where the two conditions are documented as unrelated.
What moves you there: Documentation of juvenile rheumatoid arthritis, unspecified moves the case to M08.0; the two are not reported together unless documented as unrelated.
Full comparison: M08.99 vs M08.0 →
M14.8— Excludes1 conflict (Excludes1 — generally not reported together)
Not coded here — the tabular list excludes this pair for the same encounter.
Not reported together with this code, except where the two conditions are documented as unrelated.
What moves you there: Documentation of arthropathy in Whipple's disease moves the case to M14.8; the two are not reported together unless documented as unrelated.
Full comparison: M08.99 vs M14.8 →
M05.0— Excludes1 conflict (Excludes1 — generally not reported together)
Not coded here — the tabular list excludes this pair for the same encounter.
Not reported together with this code, except where the two conditions are documented as unrelated.
What moves you there: Documentation of Felty's syndrome moves the case to M05.0; the two are not reported together unless documented as unrelated.
Full comparison: M08.99 vs M05.0 →
M33.0— Excludes1 conflict (Excludes1 — generally not reported together)
Not coded here — the tabular list excludes this pair for the same encounter.
Not reported together with this code, except where the two conditions are documented as unrelated.
What moves you there: Documentation of juvenile dermatomyositis moves the case to M33.0; the two are not reported together unless documented as unrelated.
Full comparison: M08.99 vs M33.0 →
L40.54— Excludes1 conflict (Excludes1 — generally not reported together)
Not coded here — the tabular list excludes this pair for the same encounter.
Not reported together with this code, except where the two conditions are documented as unrelated.
What moves you there: Documentation of psoriatic juvenile arthropathy moves the case to L40.54; the two are not reported together unless documented as unrelated.
Full comparison: M08.99 vs L40.54 →

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

No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

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

Other codes that name M08.99 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: M05 — Rheumatoid arthritis with rheumatoid factor (via M08.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 3 MS-DRGs: DRG 545 (MDC 08), DRG 546 (MDC 08), DRG 547 (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):MUS004 — Juvenile arthritis (default).

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 (Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders) for risk-adjusted payment.

Related risk categories

These categories interact through CMS's HCC hierarchy — one can suppress the other's risk-adjustment weight when both are present on a claim.

Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Juvenile arthritis).

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.

Contextual Map

Every relationship of M08.99 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.

Run M08.99 with this related code in Claim Check

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
M05-M14 — Inflammatory polyarthropathies[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes1 notes

M05 — Rheumatoid arthritis with rheumatoid factor[Excludes1](via M08.-): “juvenile rheumatoid arthritis (M08.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

MUS004 — Juvenile arthritis[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders [CMS-HCC]: “Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders — supersedes HCC 94 (Systemic Lupus Erythematosus and Other Specified Systemic Connective Tissue Disorders)”— CMS-HCC V28 · 2026

MS-DRG Grouper

DRG 545 — CONNECTIVE TISSUE DISORDERS WITH MCC[MS-DRG]: “CONNECTIVE TISSUE DISORDERS WITH MCC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
DRG 546 — CONNECTIVE TISSUE DISORDERS WITH CC[MS-DRG]: “CONNECTIVE TISSUE DISORDERS WITH CC (MDC 08)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
DRG 547 — CONNECTIVE TISSUE DISORDERS WITHOUT CC/MCC[MS-DRG]: “CONNECTIVE TISSUE DISORDERS 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), juvenile, multiple site[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (40)

M08 — Juvenile arthritis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M08.862 — Other juvenile arthritis, left knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M08.869 — Other juvenile arthritis, unspecified knee[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M08.87 — Other juvenile arthritis, ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M08.871 — Other juvenile arthritis, right ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M08.872 — Other juvenile arthritis, left ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M08.879 — Other juvenile arthritis, unspecified ankle and foot[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
M08.88 — Other juvenile arthritis, other specified site[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

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "M08.99 — Juvenile arthritis, unspecified, multiple sites." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/m08.99-juvenile-arthritis-unspecified-multiple-sites

Change history

FY2016 — October 1, 2015
In the code set at ICD-10-CM adoption
Juvenile arthritis, unspecified, multiple sites

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to M08.99 in its code family, with their registry titles.

View all codes in the M08 family

M08.99 ICD-10-CM Code: Juvenile arthritis, unspecified, multiple sites

Coding at a Glance

Inpatient Payment Groups (MS-DRG)

Risk Adjustment (CMS-HCC)

Coding instructions

Excludes1 — Not Coded Here

Code Also

Coder workflow for M08.99

Before you code M08.99

Choose the right path

Documentation check

Official instructions as workflow

Coding decision scenarios

Code Overview

Indexed Clinical Terms (1)

Don’t confuse M08.99 with…

Verify Before Coding

Relationships & Classification

MS-DRG Grouper Relationships (FY2026)

Related Codes

Same CMS-HCC risk category (V28)

Related risk categories

Same clinical category (CCSR)

Same Index main term, other category

Contextual Map

Hierarchy

Referenced by Excludes1 notes

Clinical classification (CCSR)

Risk adjustment (CMS-HCC)

MS-DRG Grouper

MDC crossing

Index entries

Nearest codes (40)

Change history

Sources for this page

Cite this page

Change history

Nearest Codes in This Family