M08.431 ICD-10-CM Code: Pauciarticular juvenile rheumatoid arthritis, right wrist
HCC Buddy Code Card
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FY 2026 Apr update / Diseases of the musculoskeletal system and connective tissue (M00-M99) / Inflammatory polyarthropathies (M05-M14)
M08.431
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidancePauciarticular juvenile rheumatoid arthritis, right wrist
A type of arthritis in children that affects only a few joints, specifically involving the right wrist. It causes inflammation and stiffness in the wrist joint.
Buddy Insight
Pauciarticular juvenile rheumatoid arthritis affecting the right wrist represents a chronic inflammatory condition that can severely impact hand function, fine motor skills, and activities of daily living.
CMS-HCC V28
MappedHCC 93
RAF 0.175
CMS-HCC V24
MappedHCC 40
RAF 0.307
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 40
RAF 0.0
RXHCC
MappedHCC 83
RAF 0.0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for M08.431 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for M08.431 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for M08.431 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for M08.431 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for M08.431 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for M08.431 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for M08.431 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is M08.431 an HCC code?
Yes. M08.431 maps to Rheumatoid Arthritis and Inflammatory Connective Tissue Disease under the CMS-HCC V28 risk adjustment model (and Rheumatoid Arthritis and Inflammatory Connective Tissue Disease under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. 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.
MEAT Criteria for M08.431
For M08.431to 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 M08.431 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
M08.431 is the ICD-10-CM diagnosis code for pauciarticular juvenile rheumatoid arthritis, right wrist. A type of arthritis in children that affects only a few joints, specifically involving the right wrist. It causes inflammation and stiffness in the wrist joint. M08.431 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, M08.431 maps to Rheumatoid Arthritis and Inflammatory Connective Tissue Disease (HCC 93) with a community, non-dual, aged base RAF weight of 0.175. Under the older V24 model, M08.431 mapped to the same category but with a base RAF weight of 0.307, V28 recalibrated weights across the entire model. 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 the medical record documents right wrist as the site of pauciarticular JIA involvement. Because M08.431 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 M08.431 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm the medical record documents right wrist as the site of pauciarticular JIA involvement
- •Wrist involvement is common in pauciarticular JIA; ensure this is the primary diagnosis being coded
Clinical Significance
Pauciarticular juvenile rheumatoid arthritis affecting the right wrist represents a chronic inflammatory condition that can severely impact hand function, fine motor skills, and activities of daily living. Wrist involvement in JRA is particularly concerning due to the complex anatomy and potential for growth disturbances, requiring specialized rheumatologic and orthopedic management.
Documentation Requirements
- ✓Patient age at onset (must be under 16 years)
- ✓Involvement of 4 or fewer joints throughout disease course
- ✓Documentation of right wrist joint involvement with inflammation
- ✓Absence of systemic symptoms (fever, rash, organomegaly)
- ✓Duration of symptoms (minimum 6 weeks for JRA diagnosis)
- ✓Physical examination findings of wrist joint swelling, warmth, or limited motion
- ✓Laboratory studies excluding other causes of arthritis
- ✓Assessment of functional impact on hand function and fine motor activities
Commonly Confused Codes
- •M08.3: Juvenile rheumatoid polyarthritis seronegative (affects 5 or more joints)
- •M08.2x: Juvenile rheumatoid arthritis with systemic onset (has systemic symptoms)
- •M25.531: Pain in right wrist (symptom code, not diagnostic)
- •M65.831: Other synovitis and tenosynovitis, right wrist (tendon involvement, not joint)
- •S63.001A: Unspecified dislocation of right wrist and hand, initial encounter (traumatic injury)