Question 1

What is ICD-10 code A06.6?

Accepted Answer

A06.6 is the ICD-10-CM diagnosis code for amebic brain abscess. A brain infection caused by a parasitic amoeba that forms a pus-filled cavity in the brain tissue. This is a serious condition that occurs when the parasite spreads from the intestines or liver to the brain. A06.6 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering intestinal infectious diseases (a00-a09).

A06.6 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 documentation confirms amebic etiology (caused by Entamoeba histolytica) rather than other types of brain abscess, as this distinction is critical for accurate coding.

Question 2

Is A06.6 an HCC code?

Accepted Answer

No. A06.6 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 A06.6 billable?

Accepted Answer

Yes. A06.6 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. A06.6 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 A06.6?

Accepted Answer

A06.6 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 A06.6 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 A06.6?

Accepted Answer

Verify documentation confirms amebic etiology (caused by Entamoeba histolytica) rather than other types of brain abscess, as this distinction is critical for accurate coding Ensure the abscess location is specifically documented as brain/cerebral; if documentation indicates other sites (liver, lung), use alternative A06 codes (A06.4 for liver abscess, A06.5 for lung abscess)

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A06.6

Is A06.6 an HCC code?

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Open A06.6 in the Interactive Encoder

A06.6 ICD-10-CM Code: Amebic brain abscess

HCC Buddy Code Card

A06.6

Is A06.6 an HCC code?

What This Code Means

Coding Tips

Child Codes

Code Hierarchy

Open A06.6 in the Interactive Encoder