C86.40 ICD-10-CM Code: Blastic NK-cell lymphoma not having achieved remission
C86.40 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 · free HCC coding tools
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FY 2026 Apr update / Neoplasms (C00-D49) / Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
C86.40
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceBlastic NK-cell lymphoma not having achieved remission
A rare, aggressive lymphoma caused by abnormal NK-cells with blast-like features that has not achieved remission.
Buddy Insight
Blastic NK-cell lymphoma (now more precisely classified as blastic plasmacytoid dendritic cell neoplasm) is an extremely rare, aggressive hematologic malignancy with immature blast-like morphology.
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 21
Code-level coefficient reference
Code Book Path
Inclusion Terms
Official- Blastic NK-cell lymphoma NOS
- Blastic NK-cell lymphoma with failed remission
- Blastic plasmacytoid dendritic cell neoplasm (BPDCN) NOS
- Blastic plasmacytoid dendritic cell neoplasm (BPDCN) not having achieved remission
- Blastic plasmacytoid dendritic cell neoplasm (BPDCN) with failed remission
- Blastic plasmacytoid dendritic cell neoplasm (BPDCN)Inherited from C86.4
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 C86.40. Check the code and parent instructions in the Code Book.
Excludes 1
Official- anaplastic large cell lymphoma, ALK negative (C84.7-)Inherited from C86
- anaplastic large cell lymphoma, ALK positive (C84.6-)Inherited from C86
- mature T/NK-cell lymphomas (C84.-)Inherited from C86
- other specified types of non-Hodgkin lymphoma (C85.8-)Inherited from C86
Code First
OfficialNo Code First sequencing instructions are included in this display for C86.40. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for C86.40. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for C86.40. 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 C86.40 an HCC code?
Yes. C86.40 (Blastic NK-cell lymphoma not having achieved 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: C86.40 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
- C86.40
- Description
- Blastic NK-cell lymphoma not having achieved 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 C86.40 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for C86.40
For C86.40, 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
C86.40 is the ICD-10-CM diagnosis code for blastic nk-cell lymphoma not having achieved remission. A rare, aggressive lymphoma caused by abnormal NK-cells with blast-like features that has not achieved remission. C86.40 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, C86.40 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.
Verify blastic morphology is confirmed in pathology report. For C86.40, 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 C86.40 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify blastic morphology is confirmed in pathology report
- •Ensure active disease status is documented
Clinical Significance
Blastic NK-cell lymphoma (now more precisely classified as blastic plasmacytoid dendritic cell neoplasm) is an extremely rare, aggressive hematologic malignancy with immature blast-like morphology. It often presents with skin involvement followed by rapid dissemination to bone marrow, lymph nodes, and other organs. Non-remission status carries a very poor prognosis with median survival typically under 18 months.
Documentation Requirements
- ✓Pathology confirmation with immunohistochemistry demonstrating blastic NK-cell markers (CD56, CD4, CD123) is essential.
- ✓Documentation must include disease extent, sites of involvement (skin, marrow, nodes), treatment regimen, response assessment, and explicit statement that remission has not been achieved.