Question 1

What is ICD-10 code H31.123?

Accepted Answer

H31.123 is the ICD-10-CM diagnosis code for diffuse secondary atrophy of choroid, bilateral. Widespread thinning and wasting of the choroid layer affecting both eyes that has developed as a secondary consequence of another eye condition or disease. H31.123 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).

H31.123 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.

When bilateral secondary atrophy is present, use this single code rather than coding each eye separately.

Question 2

Is H31.123 an HCC code?

Accepted Answer

No. H31.123 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 H31.123 billable?

Accepted Answer

Yes. H31.123 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. H31.123 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 H31.123?

Accepted Answer

H31.123 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 H31.123 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 H31.123?

Accepted Answer

When bilateral secondary atrophy is present, use this single code rather than coding each eye separately Ensure documentation supports that the atrophy is secondary to another identifiable condition

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H31.123

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H31.123 ICD-10-CM Code: Diffuse secondary atrophy of choroid, bilateral

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H31.123

Is H31.123 an HCC code?

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