Question 1

What is ICD-10 code A50.54?

Accepted Answer

A50.54 is the ICD-10-CM diagnosis code for Late congenital cardiovascular syphilis. It belongs to the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99). A50.54 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. A50.54 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 A50.54 an HCC code?

Accepted Answer

No. A50.54 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 A50.54 billable?

Accepted Answer

Yes. A50.54 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. A50.54 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 A50.54 map to under V28?

Accepted Answer

A50.54 does not map to a CMS-HCC V28 payment category. Check the current CMS-HCC V28 model file for payment year 2026 rather than an older V24 tip sheet.

Question 5

What does A50.54 pay in RAF?

Accepted Answer

A50.54 has no separately stated V28 community RAF weight. If it is not a V28 payment HCC, it adds nothing to a community RAF score.

Question 6

What is the V28 vs V24 difference for A50.54?

Accepted Answer

A50.54 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 A50.54 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 7

What documentation supports A50.54?

Accepted Answer

This code is used only for cardiovascular manifestations of late congenital syphilis (typically appearing after age 2); ensure the syphilis is confirmed as congenital and not acquired Do not use this code for early congenital syphilis (before age 2) or for acquired syphilis; verify documentation clearly states 'late congenital' and specifies cardiovascular involvement A50.54 is not a CMS-HCC payment code, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

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A50.54

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A50.54 ICD-10-CM Code: Late congenital cardiovascular syphilis

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A50.54

Is A50.54 an HCC code?

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