What is ICD-10 code M08.212?

M08.212 is the ICD-10-CM diagnosis code for Juvenile rheumatoid arthritis with systemic onset, left shoulder. A systemic form of childhood arthritis with fever and rash that specifically affects the left shoulder joint. M08.212 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. M08.212 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. M08.212 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. M08.212 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.

Which HCC does M08.212 map to under V28?

M08.212 maps to CMS-HCC V28 HCC 93 (Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM M08.212: Juvenile rheumatoid

M08.212 maps to CMS-HCC V28 93. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software

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Code lookupM08.212

Effective 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)

M08.212

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

Juvenile rheumatoid arthritis with systemic onset, left shoulder

A systemic form of childhood arthritis with fever and rash that specifically affects the left shoulder joint.

Buddy Insight

This diagnosis represents systemic onset juvenile rheumatoid arthritis with specific left shoulder involvement, combining severe systemic inflammatory disease with focal joint destruction.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 93

Rheumatoid Arthritis and Othe...

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 056

HHS-HCC 056 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 40

Rheumatoid Arthritis and Infl...

Code-level coefficient reference

RXHCC

Mapped

HCC 83

Rheumatoid Arthritis and Othe...

Code-level coefficient reference

Code Book Path

Official

M08.2Juvenile rheumatoid arthritis with systemic onset M08.21Juvenile rheumatoid arthritis with systemic onset, shoulder M08.212Juvenile rheumatoid arthritis with systemic onset, left shoulder

Inclusion Terms

Official

Still's disease NOSInherited from M08.2

Excludes 2

Official

arthropathic psoriasis (L40.5-)Inherited from M00-M99
certain conditions originating in the perinatal period (P04-P96)Inherited from M00-M99
certain infectious and parasitic diseases (A00-B99)Inherited from M00-M99
compartment syndrome (traumatic) (T79.A-)Inherited from M00-M99
complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from M00-M99
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)Inherited from M00-M99
endocrine, nutritional and metabolic diseases (E00-E88)Inherited from M00-M99
injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from M00-M99
neoplasms (C00-D49)Inherited from M00-M99
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from M00-M99

Related Codes

Official

M08.211Juvenile rheumatoid arthritis with systemic onset, right shoulder M08.219Juvenile rheumatoid arthritis with systemic onset, unspecified shoulder

Includes

Official

No Includes notes are included in this display for M08.212. Check the code and parent instructions in the Code Book.

Excludes 1

Official

arthropathy in Whipple's disease (M14.8)Inherited from M08, M08.2
Felty's syndrome (M05.0)Inherited from M08, M08.2
juvenile dermatomyositis (M33.0-)Inherited from M08, M08.2
psoriatic juvenile arthropathy (L40.54)Inherited from M08, M08.2
adult-onset Still's disease (M06.1-)Inherited from M08, M08.2

Code First

Official

No Code First sequencing instructions are included in this display for M08.212. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for M08.212. Check the code and parent instructions in the Code Book.

Code Also

Official

any associated underlying condition, such as:Inherited from M08
regional enteritis [Crohn's disease] (K50.-)Inherited from M08
ulcerative colitis (K51.-)Inherited from M08

Buddy Documentation Tip

HCC Buddy guidance

Physician diagnosis of systemic onset juvenile rheumatoid arthritis

Specific documentation of left shoulder joint involvement

Age of onset documented as under 16 years

Evidence of systemic manifestations (fever, rash, hepatosplenomegaly)

MEAT Support

HCC Buddy guidance

Physician diagnosis of systemic onset juvenile rheumatoid arthritis

Specific documentation of left shoulder joint involvement

Age of onset documented as under 16 years

Evidence of systemic manifestations (fever, rash, hepatosplenomegaly)

Audit Caution

HCC Buddy guidance

Using unspecified laterality when left side is documented

Coding non-systemic JRA types when systemic features present

Applying adult rheumatoid arthritis codes to pediatric patients

Missing associated systemic organ involvement

Common Mistakes

HCC Buddy guidance

M08211 — Right shoulder involvement instead of left

M08219 — Unspecified shoulder when left side documented

M08012 — Unspecified JRA left shoulder without systemic features

M06.812 — Adult RA left shoulder for patients over 16

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 M08.212 an HCC code?

Yes. M08.212 (Juvenile rheumatoid arthritis with systemic onset, left shoulder) maps to HCC 93, Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.617. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: M08.212 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: M08.212
Description: Juvenile rheumatoid arthritis with systemic onset, left shoulder
HCC (V28): HCC 93 — Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders
RAF reference coefficient: 0.617
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 93, Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders

0.617

ESRDHCC 40, Rheumatoid Arthritis and Inflammatory Connective Tissue Disease

Not separately weighted

RxHCCHCC 83, Rheumatoid Arthritis and Other Inflammatory Polyarthropathy

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work M08.212 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for M08.212

For M08.212, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

M08.212 is the ICD-10-CM diagnosis code for juvenile rheumatoid arthritis with systemic onset, left shoulder. A systemic form of childhood arthritis with fever and rash that specifically affects the left shoulder joint. M08.212 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, M08.212 maps to Rheumatoid Arthritis and Other Specified Inflammatory Rheumatic Disorders (HCC 93) with a source-labeled community, non-dual, aged reference coefficient of 0.617. No V24 mapping is shown for M08.212; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Use this code when systemic onset juvenile rheumatoid arthritis is documented with left shoulder involvement. For M08.212, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for M08.212 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code when systemic onset juvenile rheumatoid arthritis is documented with left shoulder involvement
•Confirm left-sided involvement is explicitly stated in clinical documentation

Clinical Significance

This diagnosis represents systemic onset juvenile rheumatoid arthritis with specific left shoulder involvement, combining severe systemic inflammatory disease with focal joint destruction. The systemic nature significantly increases morbidity risk and requires aggressive immunosuppressive treatment to prevent life-threatening complications.