ICD-10 C91.10
Billable / Specific HCC v28: 10 CCChronic lymphocytic leukemia of B-cell type not having achieved remission
About ICD-10-CM C91.10
ICD-10-CM code C91.10 represents Chronic lymphocytic leukemia of B-cell type not having achieved remission. This is a billable/specific code in the chapter (block C91). The 2026 edition of ICD-10-CM C91.10 became effective on October 1, 2025.
Coding Tips for C91.10
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
C91.10 is a CMS-HCC v28 risk-adjustment code (category 10). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
C91.10 is designated CC for MS-DRG grouping. On inpatient claims, this code can shift the DRG to the with-CC variant when documented as a present-on-admission secondary diagnosis. Hospital CDI programs flag CC opportunities during chart review. Failure to capture this code may leave 30 to 80 percent of the inpatient stay revenue unrealized.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under C91.10. Per CMS ICD-10-CM Tabular 2026.
- Chronic lymphocytic leukemia of B-cell type with failed remission
- Chronic lymphocytic leukemia of B-cell type NOS
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Inpatient DRG Impact, CC
codes Chronic lymphocytic leukemia of B-cell type not having achieved remission. As a Complication/Comorbidity (CC), this contributes to DRG severity adjustment when documented alongside the principal diagnosis.
Medicare LCD Coverage for C91.10
Local Coverage Determinations (LCDs) from CMS MACs that list C91.10 as a covered diagnosis.
Showing top 10 of 1,365 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C91.10.
5 Medicare
CPT Codes Commonly Billed with C91.10
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 0077U CMS LCD: Billing and Coding: Mass Spectrometry (MS) Testing in Monoclonal Gammopathy (MG) CMS LCD
- J0840 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
- J0850 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
- 90371 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
- 90375 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
- J1573 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
- J1569 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
- J1459 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
- J1557 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
- J1556 CMS LCD: Billing and Coding: Immune Globulins CMS LCD
Convert C91.10 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| C91.10 | 20410 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To C91.10
Other codes in section C81-C96 (Malignant neoplasms of lymphoid, hematopoietic and related tissue).
ICD-10 C91.10, Billing FAQ
Is ICD-10 code C91.10 billable? +
Yes, C91.10 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to C91.10? +
ICD-10 C91.10 includes: Chronic lymphocytic leukemia of B-cell type with failed remission; Chronic lymphocytic leukemia of B-cell type NOS.
Does C91.10 affect Medicare Advantage HCC risk adjustment? +
Yes. C91.10 maps to CMS-HCC v28 category 10. Capture this diagnosis annually for accurate Medicare Advantage risk score.
Is C91.10 a CC or MCC for inpatient DRG? +
Yes, this code is designated as CC. Documenting as a secondary diagnosis on inpatient claims can shift the DRG to a higher-weighted category.
What CPT codes are commonly billed with C91.10? +
Procedures frequently paired with C91.10 include: 0077U, J0840, J0850, 90371, 90375.
What ICD-9 codes does C91.10 map to? +
Per CMS GEMs, C91.10 maps to ICD-9 codes: 20410. Useful for legacy data review and historical claim analysis.
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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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