Question 1

What is ICD-10 code A66.5?

Accepted Answer

A66.5 is the ICD-10-CM diagnosis code for Gangosa. It belongs to the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99). A66.5 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. A66.5 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Question 2

Is A66.5 an HCC code?

Accepted Answer

A66.5 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

Question 3

Is A66.5 billable?

Accepted Answer

Yes. A66.5 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. A66.5 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

Which HCC does A66.5 map to under V28?

Accepted Answer

A66.5 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

Question 5

What RAF reference is published for A66.5?

Accepted Answer

A66.5 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

Question 6

What is the V28 vs V24 difference for A66.5?

Accepted Answer

A66.5 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

Question 7

What documentation supports A66.5?

Accepted Answer

Gangosa is a late manifestation of yaws, so ensure the underlying yaws diagnosis is also documented and coded appropriately (A66.0-A66.4 for earlier stages) This code is rarely seen in developed countries and is primarily associated with tropical and subtropical regions; verify the patient's geographic history or travel background when coding this diagnosis A66.5 is not a CMS-HCC V28 payment code in the verified current source, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

Question 8

Can A66.5 be a primary diagnosis?

Accepted Answer

Yes. A66.5 carries no code-first instruction in the FY2026 tabular, so it can be the first-listed diagnosis when it is the condition chiefly responsible for the encounter and the note supports it, and it can also be reported as a secondary diagnosis. For risk adjustment the order does not matter; the V28 category is the same either way.

Question 9

Which codes cannot be reported with A66.5?

Accepted Answer

The Excludes1 note that applies to A66.5 lists certain localized infections - see body system-related chapters. An Excludes1 condition is not reported together with A66.5; report one or the other, unless the two conditions are unrelated, which the ICD-10-CM Official Guidelines (Section I.A.12.a) allow. The Excludes2 note lists carrier or suspected carrier of infectious disease (Z22.-); infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-); infectious and parasitic diseases specific to the perinatal period (P35-P39); influenza and other acute respiratory infections (J00-J22); and 2 more (see the notes on this page); those are separate conditions that may be reported together with A66.5 when both are documented.

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A66.5

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A66.5 ICD-10-CM Code: Gangosa

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A66.5

Is A66.5 an HCC code?

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Work A66.5 in HCC Buddy