ICD-10 C91.1
Non-Billable HeaderChronic lymphocytic leukemia of B-cell type
About ICD-10-CM C91.1
ICD-10-CM code C91.1 represents Chronic lymphocytic leukemia of B-cell type. This is a non-billable header code in the chapter (block C91). The 2026 edition of ICD-10-CM C91.1 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under C91.1. Per CMS ICD-10-CM Tabular 2026.
- Lymphoplasmacytic leukemia
- Richter syndrome
Type 1 Excludes
Pure excludes, these codes can never be coded together with C91.1. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- lymphoplasmacytic lymphoma (C83.0-)
Medicare LCD Coverage for C91.1
Local Coverage Determinations (LCDs) from CMS MACs that list C91.1 as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C91.1.
Our payer policy database covers Aetna, Cigna, Anthem, BCBS, Humana, and Medicare Advantage plans, but C91.1 doesn't currently appear in any indexed policy. The code may still be covered under standard plan benefits.
CPT Codes Commonly Billed with C91.1
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To C91.1
Other codes in section C81-C96 (Malignant neoplasms of lymphoid, hematopoietic and related tissue).
ICD-10 C91.1, Billing FAQ
Is ICD-10 code C91.1 billable? +
No, C91.1 is a non-billable header code. Use a more specific child code from block C91 when submitting claims.
What other names or terms map to C91.1? +
ICD-10 C91.1 includes: Lymphoplasmacytic leukemia; Richter syndrome.
What codes are Type 1 Excludes for C91.1? +
Type 1 Excludes (never code together with C91.1): lymphoplasmacytic lymphoma (C83.0-)
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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