Question 1

What is ICD-10 code H21.231?

Accepted Answer

H21.231 is the ICD-10-CM diagnosis code for Degeneration of iris (pigmentary), right eye. It belongs to the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59). H21.231 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. H21.231 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Question 2

Is H21.231 an HCC code?

Accepted Answer

No. H21.231 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 H21.231 billable?

Accepted Answer

Yes. H21.231 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. H21.231 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

Which HCC does H21.231 map to under V28?

Accepted Answer

H21.231 does not map to a CMS-HCC V28 payment category. Check the current CMS-HCC V28 model file for payment year 2026 rather than an older V24 tip sheet.

Question 5

What does H21.231 pay in RAF?

Accepted Answer

H21.231 has no separately stated V28 community RAF weight. If it is not a V28 payment HCC, it adds nothing to a community RAF score.

Question 6

What is the V28 vs V24 difference for H21.231?

Accepted Answer

H21.231 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 community model rewards H21.231 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's V28/V24 community RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a community payment HCC.

Question 7

What documentation supports H21.231?

Accepted Answer

Ensure laterality is correctly specified - this code is specifically for the right eye; use H21.232 for left eye and H21.233 for bilateral cases Verify that pigmentary degeneration is documented in the clinical record and distinguish it from other iris conditions like atrophy or heterochromia H21.231 is not a CMS-HCC payment code, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

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H21.231

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H21.231 ICD-10-CM Code: Degeneration of iris (pigmentary), right eye

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H21.231

Is H21.231 an HCC code?

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Work H21.231 in HCC Buddy