Question 1

What is ICD-10 code M02.221?

Accepted Answer

M02.221 is the ICD-10-CM diagnosis code for postimmunization arthropathy, right elbow. Joint inflammation in the right elbow that develops as a reaction to a vaccination. M02.221 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering infectious arthropathies (m00-m02).

M02.221 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Confirm the affected joint is the right elbow; do not use for left or bilateral elbow involvement.

Question 2

Is M02.221 an HCC code?

Accepted Answer

No. M02.221 is a billable ICD-10-CM code but does not map to any payment HCC category under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can still be reported on Medicare Advantage encounter data submissions, but it does not contribute to the beneficiary's Risk Adjustment Factor (RAF) score and therefore does not affect the risk-adjusted capitation payment to the plan. V28 reached 100% phase-in for payment year 2026.

Question 3

Is M02.221 billable?

Accepted Answer

Yes. M02.221 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. M02.221 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.

Question 4

What is the V28 vs V24 difference for M02.221?

Accepted Answer

M02.221 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards M02.221 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

Question 5

What should coders know when reporting M02.221?

Accepted Answer

Confirm the affected joint is the right elbow; do not use for left or bilateral elbow involvement Document the vaccine type and administration date for medical-legal documentation

M02.221

Is M02.221 an HCC code?

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Open M02.221 in the Interactive Encoder