Question 1

What is ICD-10 code M65.029?

Accepted Answer

M65.029 is the ICD-10-CM diagnosis code for abscess of tendon sheath, unspecified upper arm. A bacterial infection or abscess in the tendon sheath of the upper arm when the side is not specified. M65.029 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering disorders of synovium and tendon (m65-m67).

M65.029 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.

Use this code only when laterality is not documented or is unclear.

Question 2

Is M65.029 an HCC code?

Accepted Answer

No. M65.029 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 M65.029 billable?

Accepted Answer

Yes. M65.029 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. M65.029 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 M65.029?

Accepted Answer

M65.029 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 M65.029 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 M65.029?

Accepted Answer

Use this code only when laterality is not documented or is unclear Attempt to clarify with the provider whether the condition affects the right or left arm

HCC Buddy Code Card

M65.029

Is M65.029 an HCC code?

Get the V28 RAF + MEAT cheat sheet

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Work M65.029 in HCC Buddy

M65.029 ICD-10-CM Code: Abscess of tendon sheath, unspecified upper arm

HCC Buddy Code Card

M65.029

Is M65.029 an HCC code?

Get the V28 RAF + MEAT cheat sheet

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Work M65.029 in HCC Buddy