Question 1

What is ICD-10 code H10.423?

Accepted Answer

H10.423 is the ICD-10-CM diagnosis code for simple chronic conjunctivitis, bilateral. A chronic inflammation of the clear membrane covering the white part of both eyes, characterized by mild symptoms and minimal papillary response. H10.423 sits in the ICD-10-CM chapter for diseases of the eye and adnexa (h00-h59), within the section covering disorders of conjunctiva (h10-h11).

H10.423 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.

Verify bilateral involvement is clearly documented before coding.

Question 2

Is H10.423 an HCC code?

Accepted Answer

No. H10.423 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 H10.423 billable?

Accepted Answer

Yes. H10.423 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. H10.423 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 H10.423?

Accepted Answer

H10.423 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 H10.423 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 H10.423?

Accepted Answer

Verify bilateral involvement is clearly documented before coding This is a mild form of chronic conjunctivitis, so ensure more severe types are ruled out

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H10.423

Is H10.423 an HCC code?

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Open H10.423 in the Interactive Encoder

H10.423 ICD-10-CM Code: Simple chronic conjunctivitis, bilateral

HCC Buddy Code Card

H10.423

Is H10.423 an HCC code?

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Open H10.423 in the Interactive Encoder