C85.10 ICD-10-CM Code: Unspecified B-cell lymphoma, unspecified site
C85.10 maps to CMS-HCC V28 21. 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)
C85.10
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceUnspecified B-cell lymphoma, unspecified site
A cancer of B-cells (a type of immune cell) where the specific location of the cancer is not documented or specified.
Buddy Insight
Unspecified B-cell lymphoma at an unspecified site is a highly nonspecific code that should trigger a coding query whenever possible.
CMS-HCC V28
MappedHCC 21
Coefficient HCC 21: 0.671 (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 21
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for C85.10. 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 C85.10. Check the code and parent instructions in the Code Book.
Excludes 1
Official- other specified types of T/NK-cell lymphoma (C86.-)Inherited from C85
- personal history of non-Hodgkin lymphoma (Z85.72)Inherited from C85
Code First
OfficialNo Code First sequencing instructions are included in this display for C85.10. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for C85.10. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for C85.10. 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 C85.10 an HCC code?
Yes. C85.10 (Unspecified B-cell lymphoma, unspecified site) maps to HCC 21, Lymphoma and Other Cancers under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.671. 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: C85.10 is billable and maps to V28 HCC 21, Lymphoma and Other Cancers. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- C85.10
- Description
- Unspecified B-cell lymphoma, unspecified site
- HCC (V28)
- HCC 21 — Lymphoma and Other Cancers
- RAF reference coefficient
- 0.671
- 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 C85.10 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for C85.10
For C85.10, 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
C85.10 is the ICD-10-CM diagnosis code for unspecified b-cell lymphoma, unspecified site. A cancer of B-cells (a type of immune cell) where the specific location of the cancer is not documented or specified. C85.10 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, C85.10 maps to Lymphoma and Other Cancers (HCC 21) with a source-labeled community, non-dual, aged reference coefficient of 0.671. No V24 mapping is shown for C85.10; use the applicable model and payment year when reviewing the V28 mapping. 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.
This is a less specific code; attempt to determine the anatomical site from clinical documentation before using this code. For C85.10, 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 C85.10 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a less specific code; attempt to determine the anatomical site from clinical documentation before using this code
- •If site is documented, use the more specific C85.1x codes instead
Clinical Significance
Unspecified B-cell lymphoma at an unspecified site is a highly nonspecific code that should trigger a coding query whenever possible. B-cell lymphomas comprise approximately 85% of all non-Hodgkin lymphomas and have vastly different prognoses depending on subtype. This code should be considered a placeholder pending more specific pathology results and anatomical documentation.
Documentation Requirements
- ✓Pathology confirming B-cell lineage (CD20+, CD19+, PAX5+) — at minimum, immunohistochemistry results
- ✓Attempt to obtain specific B-cell subtype: diffuse large B-cell, follicular, mantle cell, marginal zone, Burkitt, etc.
- ✓Query for anatomical site of disease based on imaging or clinical examination findings
- ✓Staging workup results including CT/PET and bone marrow biopsy
Commonly Confused Codes
- •C83.30 (Diffuse large B-cell lymphoma, unspecified site): DLBCL is the most common B-cell lymphoma; if documented, use C83.3x instead of C85.1x
- •C82.00 (Follicular lymphoma grade I, unspecified site): Follicular lymphoma has its own specific code series (C82)
- •C83.10 (Mantle cell lymphoma, unspecified site): Mantle cell lymphoma should be coded to C83.1x, not C85.1x
- •C85.90 (Non-Hodgkin lymphoma, unspecified, unspecified site): C85.1 is more specific (identifies B-cell lineage) than C85.9