M08.08 ICD-10-CM Code: Unspecified juvenile rheumatoid arthritis, vertebrae
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)
M08.08
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceUnspecified juvenile rheumatoid arthritis, vertebrae
A type of arthritis that develops in children, affecting the spine and vertebrae, causing inflammation and joint damage.
Buddy Insight
Juvenile rheumatoid arthritis affecting the vertebrae represents a serious form of pediatric inflammatory spine disease that can lead to spinal fusion and significant disability.
CMS-HCC V28
MappedHCC 93
RAF 0.617
CMS-HCC V24
MappedHCC 40
RAF 0.421
ACA/HHS
MappedHCC 56
Varies by metal level
ESRD/PACE
MappedHCC 40
RAF 0.058
RXHCC
MappedHCC 83
RAF 0.222
Code Book Path
Inclusion Terms
Official- Juvenile rheumatoid arthritis with or without rheumatoid factor
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for M08.08 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for M08.08 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for M08.08 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for M08.08 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for M08.08 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for M08.08 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 M08.08 an HCC code?
Yes. M08.08 (Unspecified juvenile rheumatoid arthritis, vertebrae) 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: M08.08 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
- M08.08
- Description
- Unspecified juvenile rheumatoid arthritis, vertebrae
- HCC (V28)
- HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders
- RAF
- 0.617
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
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 M08.08 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for M08.08
For M08.08 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 M08.08 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
M08.08 is the ICD-10-CM diagnosis code for unspecified juvenile rheumatoid arthritis, vertebrae. A type of arthritis that develops in children, affecting the spine and vertebrae, causing inflammation and joint damage. M08.08 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, M08.08 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, M08.08 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.
This code does not require laterality specification as it applies to the vertebral column. Because M08.08 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 M08.08 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code does not require laterality specification as it applies to the vertebral column
- •Document the specific vertebral levels affected if available for clinical clarity
Clinical Significance
Juvenile rheumatoid arthritis affecting the vertebrae represents a serious form of pediatric inflammatory spine disease that can lead to spinal fusion and significant disability. This axial involvement requires specialized care and monitoring for growth abnormalities and spinal deformities.
Documentation Requirements
- ✓Physician diagnosis of juvenile rheumatoid arthritis
- ✓Documentation of vertebral/spinal involvement
- ✓Age of onset documented as under 16 years
- ✓Evidence of inflammatory spinal disease
- ✓Imaging studies showing vertebral changes
- ✓Assessment of spinal mobility and function
- ✓Treatment plan including anti-inflammatory therapy
- ✓Monitoring for spinal growth abnormalities