Question 1

What is ICD-10 code A18.50?

Accepted Answer

A18.50 is the ICD-10-CM diagnosis code for tuberculosis of eye, unspecified. This code describes a tuberculosis infection affecting the eye when the specific part of the eye involved is not documented or specified. Tuberculosis can spread to various eye structures and cause inflammation and vision problems. A18.50 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering tuberculosis (a15-a19).

A18.50 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.

Query the provider if documentation specifies which part of the eye is affected (cornea, uvea, retina, etc.) as more specific A18.5x codes may be more accurate.

Question 2

Is A18.50 an HCC code?

Accepted Answer

No. A18.50 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 A18.50 billable?

Accepted Answer

Yes. A18.50 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. A18.50 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 A18.50?

Accepted Answer

A18.50 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 A18.50 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 A18.50?

Accepted Answer

Query the provider if documentation specifies which part of the eye is affected (cornea, uvea, retina, etc.) as more specific A18.5x codes may be more accurate Ensure tuberculosis has been confirmed through testing; this code should only be used when TB of the eye is documented, not suspected

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A18.50

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A18.50 ICD-10-CM Code: Tuberculosis of eye, unspecified

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A18.50

Is A18.50 an HCC code?

What This Code Means

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Child Codes

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Work A18.50 in HCC Buddy