Question 1

What is ICD-10 code H50.661?

Accepted Answer

H50.661 is the ICD-10-CM diagnosis code for superior oblique muscle entrapment, right eye. The superior oblique muscle in the right eye is trapped or restricted, affecting eye movement and causing vertical diplopia or eye misalignment. H50.661 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of ocular muscles, binocular movement, accommodation and refraction (h49-h52).

H50.661 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.

Superior oblique entrapment is less common than rectus muscle entrapment; verify diagnosis carefully.

Question 2

Is H50.661 an HCC code?

Accepted Answer

No. H50.661 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 H50.661 billable?

Accepted Answer

Yes. H50.661 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. H50.661 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 H50.661?

Accepted Answer

H50.661 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 H50.661 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 H50.661?

Accepted Answer

Superior oblique entrapment is less common than rectus muscle entrapment; verify diagnosis carefully This code is specific to the right eye; confirm laterality in documentation

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H50.661

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H50.661 ICD-10-CM Code: Superior oblique muscle entrapment, right eye

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H50.661

Is H50.661 an HCC code?

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