C91.31 ICD-10-CM Code: Prolymphocytic leukemia of B-cell type, in remission
C91.31 maps to CMS-HCC V28 19. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC coding software
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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
C91.31
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceProlymphocytic leukemia of B-cell type, in remission
A rare blood cancer (prolymphocytic leukemia) affecting B-cells that has responded well to treatment and is in remission.
Buddy Insight
Prolymphocytic leukemia of B-cell type in remission indicates that this rare aggressive leukemia has responded to treatment.
CMS-HCC V28
MappedHCC 19
Coefficient HCC 19: 1.798 (Community Non-Dual Aged (CNA))
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 010
Code-level coefficient reference
ESRD/PACE
MappedHCC 10
Code-level coefficient reference
RXHCC
MappedHCC 19
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for C91.31. Check the code and parent instructions in the Code Book.
Excludes 2
Official- Kaposi's sarcoma of lymph nodes (C46.3)Inherited from C81-C96
- secondary and unspecified neoplasm of lymph nodes (C77.-)Inherited from C81-C96
- secondary neoplasm of bone marrow (C79.52)Inherited from C81-C96
- secondary neoplasm of spleen (C78.89)Inherited from C81-C96
Related Codes
Includes
OfficialNo Includes notes are included in this display for C91.31. Check the code and parent instructions in the Code Book.
Excludes 1
Official- personal history of leukemia (Z85.6)Inherited from C91
Code First
OfficialNo Code First sequencing instructions are included in this display for C91.31. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for C91.31. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for C91.31. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is C91.31 an HCC code?
Yes. C91.31 (Prolymphocytic leukemia of B-cell type, in remission) maps to HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 1.798. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: C91.31 is billable and maps to V28 HCC 19, Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- C91.31
- Description
- Prolymphocytic leukemia of B-cell type, in remission
- HCC (V28)
- HCC 19 — Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers
- RAF reference coefficient
- 1.798
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work C91.31 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for C91.31
For C91.31, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Coder workflow notes
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What This Code Means
C91.31 is the ICD-10-CM diagnosis code for prolymphocytic leukemia of b-cell type, in remission. A rare blood cancer (prolymphocytic leukemia) affecting B-cells that has responded well to treatment and is in remission. C91.31 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering malignant neoplasms of lymphoid, hematopoietic and related tissue (c81-c96).
Under the CMS-HCC V28 risk adjustment model, C91.31 maps to Myelodysplastic Syndromes, Multiple Myeloma, and Other Cancers (HCC 19) with a source-labeled community, non-dual, aged reference coefficient of 1.798. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
The fifth character '1' indicates remission status - ensure documentation confirms remission has been achieved. For C91.31, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for C91.31 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The fifth character '1' indicates remission status - ensure documentation confirms remission has been achieved
- •Remission status should be clearly documented in clinical notes for accurate coding
Clinical Significance
Prolymphocytic leukemia of B-cell type in remission indicates that this rare aggressive leukemia has responded to treatment. Remission in B-PLL is relatively uncommon given its aggressive nature and may be achieved through combination chemotherapy or targeted agents. Even in remission, patients require close surveillance due to high relapse risk.
Documentation Requirements
- ✓Provider must explicitly document remission status and the criteria used to determine remission (blood counts, imaging, bone marrow assessment).
- ✓Treatment regimen that achieved remission and date of remission should be recorded.
- ✓Ongoing surveillance plan must be documented, including frequency of follow-up labs and imaging.
Commonly Confused Codes
- •C91.30 (B-PLL not in remission) and C91.32 (B-PLL in relapse) represent different disease statuses.
- •C91.11 (B-CLL in remission) should not be used for B-PLL, as they are distinct entities with different prognoses.
- •C91.91 (lymphoid leukemia, unspecified, in remission) is a less specific alternative that should be avoided when B-PLL is confirmed.