Question 1

What is ICD-10 code M61.452?

Accepted Answer

M61.452 is the ICD-10-CM diagnosis code for other calcification of muscle, left thigh. Calcium deposits have formed in the muscles of the left thigh, which can cause stiffness and reduced movement in that area. M61.452 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering disorders of muscles (m60-m63).

M61.452 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 left thigh laterality is explicitly documented in the clinical notes.

Question 2

Is M61.452 an HCC code?

Accepted Answer

No. M61.452 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 M61.452 billable?

Accepted Answer

Yes. M61.452 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. M61.452 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 M61.452?

Accepted Answer

M61.452 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 M61.452 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 M61.452?

Accepted Answer

Confirm left thigh laterality is explicitly documented in the clinical notes Distinguish from heterotopic ossification (M61.5x) which involves bone formation rather than simple calcification

HCC Buddy Code Card

M61.452

Is M61.452 an HCC code?

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Work M61.452 in HCC Buddy

M61.452 ICD-10-CM Code: Other calcification of muscle, left thigh

HCC Buddy Code Card

M61.452

Is M61.452 an HCC code?

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Work M61.452 in HCC Buddy