What is ICD-10 code M08.3?

M08.3 is the ICD-10-CM diagnosis code for Juvenile rheumatoid polyarthritis (seronegative). A type of childhood arthritis affecting multiple joints where blood tests for rheumatoid factor are negative. It belongs to the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99). M08.3 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. M08.3 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. M08.3 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. M08.3 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for M08.3?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For M08.3, V28 maps to Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders at RAF 0.617 while V24 mapped to Rheumatoid Arthritis and Inflammatory Connective Tissue Disease at RAF 0.421. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting M08.3?

Confirm seronegative status (negative RF and anti-CCP antibodies) is documented Polyarticular presentation requires involvement of five or more joints Because M08.3 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

2026 ICD-10-CM M08.3: Juvenile rheumatoid

ICD-10-CM Code View

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Code lookupM08.3Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Inflammatory polyarthropathies (M05-M14)

M08.3

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Juvenile rheumatoid polyarthritis (seronegative)

A type of childhood arthritis affecting multiple joints where blood tests for rheumatoid factor are negative.

Buddy Insight

Juvenile rheumatoid polyarthritis (seronegative) represents a significant chronic childhood condition affecting multiple joints without systemic features or positive rheumatoid factor.

CMS-HCC V28

Mapped

HCC 93

Rheumatoid Arthritis and Othe...

RAF 0.617

CMS-HCC V24

Mapped

HCC 40

Rheumatoid Arthritis and Infl...

RAF 0.421

ACA/HHS

Mapped

HCC 56

HHS-HCC 56

Varies by metal level

ESRD/PACE

Mapped

HCC 40

Rheumatoid Arthritis and Infl...

RAF 0.058

RXHCC

Mapped

HCC 83

Rheumatoid Arthritis and Infl...

RAF 0.222

Code Book Path

Official

M08Juvenile arthritis

M08.3Juvenile rheumatoid polyarthritis (seronegative)

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for M08.3 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for M08.3 in this effective period.

Related Child Codes

Official

M08.0Unspecified juvenile rheumatoid arthritis

M08.1Juvenile ankylosing spondylitis

M08.2Juvenile rheumatoid arthritis with systemic onset

M08.4Pauciarticular juvenile rheumatoid arthritis

M08.8Other juvenile arthritis

Includes

Official

ICD-10-CM does not list Includes notes for M08.3 in this effective period.

Excludes 1

Official

arthropathy in Whipple's disease (M14.8)
Felty's syndrome (M05.0)
juvenile dermatomyositis (M33.0-)
psoriatic juvenile arthropathy (L40.54)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for M08.3 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for M08.3 in this effective period.

Code Also

Official

any associated underlying condition, such as:
regional enteritis [Crohn's disease] (K50.-)
ulcerative colitis (K51.-)

Buddy Documentation Tip

HCC Buddy guidance

Patient age at onset (must be under 16 years)

Involvement of 5 or more joints within first 6 months of disease

Negative rheumatoid factor testing documented

Absence of systemic symptoms (fever, rash, organomegaly)

MEAT Support

HCC Buddy guidance

Patient age at onset (must be under 16 years)

Involvement of 5 or more joints within first 6 months of disease

Negative rheumatoid factor testing documented

Absence of systemic symptoms (fever, rash, organomegaly)

Audit Caution

HCC Buddy guidance

Using this code when rheumatoid factor is positive (should use different classification)

Coding when fewer than 5 joints are involved (should use pauciarticular codes)

Including patients with systemic symptoms (should use systemic onset codes)

Coding adult rheumatoid arthritis when disease began in childhood

Common Mistakes

HCC Buddy guidance

M08.2x — Juvenile rheumatoid arthritis with systemic onset (has systemic features like fever, rash)

M08.4x — Pauciarticular juvenile rheumatoid arthritis (affects 4 or fewer joints)

M08.0x — Unclassified juvenile rheumatoid arthritis (doesn't fit typical patterns)

M06.9 — Rheumatoid arthritis, unspecified (for adult-onset disease)

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is M08.3 an HCC code?

Yes. M08.3 (Juvenile rheumatoid polyarthritis (seronegative)) maps to Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders under the CMS-HCC V28 risk adjustment model (and Rheumatoid Arthritis and Inflammatory Connective Tissue Disease under V24), with a community non-dual aged RAF of 0.617. It is billable for payment year 2026.

Coder answer: M08.3 is billable and maps to V28 HCC 93, Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: M08.3
Description: Juvenile rheumatoid polyarthritis (seronegative)
HCC (V28): HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders
RAF: 0.617
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 93, Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders

0.617

V24HCC 40, Rheumatoid Arthritis and Inflammatory Connective Tissue Disease

0.421

ESRDHCC 40, Rheumatoid Arthritis and Inflammatory Connective Tissue Disease

0.058

RxHCCHCC 83, Rheumatoid Arthritis and Inflammatory Connective Tissue Disease

0.222

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work M08.3 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for M08.3

For M08.3 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed M08.3 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

M08.3 is the ICD-10-CM diagnosis code for juvenile rheumatoid polyarthritis (seronegative). A type of childhood arthritis affecting multiple joints where blood tests for rheumatoid factor are negative. M08.3 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering inflammatory polyarthropathies (m05-m14).

Under the CMS-HCC V28 risk adjustment model, M08.3 maps to Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders (HCC 93) with a community, non-dual, aged base RAF weight of 0.617. Under the older CMS-HCC V24 model, M08.3 maps to Rheumatoid Arthritis and Inflammatory Connective Tissue Disease (HCC 40) with a community, non-dual, aged base RAF weight of 0.421. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Confirm seronegative status (negative RF and anti-CCP antibodies) is documented. Because M08.3 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M08.3 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Confirm seronegative status (negative RF and anti-CCP antibodies) is documented
•Polyarticular presentation requires involvement of five or more joints

Clinical Significance

Juvenile rheumatoid polyarthritis (seronegative) represents a significant chronic childhood condition affecting multiple joints without systemic features or positive rheumatoid factor. This diagnosis requires ongoing rheumatologic care, potential for joint destruction, and significant impact on growth and development, particularly in young girls who are more commonly affected.

Documentation Requirements

✓Patient age at onset (must be under 16 years)
✓Involvement of 5 or more joints within first 6 months of disease
✓Negative rheumatoid factor testing documented
✓Absence of systemic symptoms (fever, rash, organomegaly)
✓Duration of symptoms (minimum 6 weeks for JRA diagnosis)
✓Physical examination findings of multiple joint inflammation
✓Laboratory evidence of inflammation (elevated ESR, CRP)
✓Exclusion of other causes of polyarthritis

Commonly Confused Codes

•M08.2x: Juvenile rheumatoid arthritis with systemic onset (has systemic features like fever, rash)
•M08.4x: Pauciarticular juvenile rheumatoid arthritis (affects 4 or fewer joints)
•M08.0x: Unclassified juvenile rheumatoid arthritis (doesn't fit typical patterns)
•M06.9: Rheumatoid arthritis, unspecified (for adult-onset disease)
•M08.1x: Juvenile ankylosing spondylitis (primarily affects spine and sacroiliac joints)