Question 1

What is ICD-10 code H35.429?

Accepted Answer

H35.429 is the ICD-10-CM diagnosis code for microcystoid degeneration of retina, unspecified eye. Small cyst-like formations in the outer edges of the retina when the specific eye affected is not documented or specified. H35.429 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of choroid and retina (h30-h36).

H35.429 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.

This unspecified code should be used only when laterality cannot be determined.

Question 2

Is H35.429 an HCC code?

Accepted Answer

No. H35.429 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 H35.429 billable?

Accepted Answer

Yes. H35.429 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. H35.429 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 H35.429?

Accepted Answer

H35.429 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 H35.429 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 H35.429?

Accepted Answer

This unspecified code should be used only when laterality cannot be determined Attempt to clarify with provider documentation whether one or both eyes are affected

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H35.429

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H35.429 ICD-10-CM Code: Microcystoid degeneration of retina, unspecified eye

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H35.429

Is H35.429 an HCC code?

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What This Code Means

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Work H35.429 in HCC Buddy