Question 1

What is ICD-10 code B64?

Accepted Answer

B64 is the ICD-10-CM diagnosis code for unspecified protozoal disease. An infection caused by a single-celled parasitic organism, but the specific type of organism has not been identified or determined. B64 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering protozoal diseases (b50-b64).

B64 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.

This is the least specific protozoan code; use only when organism cannot be identified despite testing.

Question 2

Is B64 an HCC code?

Accepted Answer

No. B64 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 B64 billable?

Accepted Answer

Yes. B64 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. B64 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 B64?

Accepted Answer

B64 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 B64 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 5

What should coders know when reporting B64?

Accepted Answer

This is the least specific protozoan code; use only when organism cannot be identified despite testing Encourage further testing or documentation to assign a more specific code

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B64

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B64 ICD-10-CM Code: Unspecified protozoal disease

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B64

Is B64 an HCC code?

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What This Code Means

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