Question 1

What is ICD-10 code M65.942?

Accepted Answer

M65.942 is the ICD-10-CM diagnosis code for unspecified synovitis and tenosynovitis, left hand. Inflammation of the tissue lining the tendons in the left hand, cause unknown. This causes pain, swelling, and difficulty moving the hand. M65.942 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).

M65.942 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 hand laterality is documented in the clinical notes before coding.

Question 2

Is M65.942 an HCC code?

Accepted Answer

No. M65.942 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 M65.942 billable?

Accepted Answer

Yes. M65.942 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. M65.942 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 M65.942?

Accepted Answer

M65.942 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 M65.942 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 M65.942?

Accepted Answer

Confirm left hand laterality is documented in the clinical notes before coding Do not use this code if a specific etiology (such as infection or rheumatoid arthritis) is documented

M65.942

Is M65.942 an HCC code?

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Open M65.942 in the Interactive Encoder