Question 1

What is ICD-10 code B91?

Accepted Answer

B91 is the ICD-10-CM diagnosis code for sequelae of poliomyelitis. Permanent neurological complications from poliomyelitis (polio), such as paralysis or muscle weakness that persists after the acute infection has resolved. B91 sits in the ICD-10-CM chapter for certain infectious and parasitic diseases (a00-b99), within the section covering sequelae of infectious and parasitic diseases (b90-b94).

B91 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.

Document the specific residual effects such as paralysis, muscle atrophy, or weakness affecting particular limbs or body regions.

Question 2

Is B91 an HCC code?

Accepted Answer

No. B91 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 B91 billable?

Accepted Answer

Yes. B91 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. B91 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 B91?

Accepted Answer

B91 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 B91 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 B91?

Accepted Answer

Document the specific residual effects such as paralysis, muscle atrophy, or weakness affecting particular limbs or body regions This code applies to patients with a history of polio infection; ensure the acute infection is not currently active

B91

Is B91 an HCC code?

What This Code Means

Coding Tips

Excludes 1 — Do NOT code together

Code Hierarchy

Open B91 in the Interactive Encoder