D47.02 ICD-10-CM Code: Systemic mastocytosis
HCC Buddy Code Card
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FY 2026 Apr update / Neoplasms (C00-D49) / Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes (D37-D48)
D47.02
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceSystemic mastocytosis
An abnormal growth of mast cells affecting multiple body systems beyond the skin, potentially involving organs like the bone marrow, liver, or spleen.
Buddy Insight
Systemic mastocytosis is a clonal mast cell disorder involving extracutaneous organs, most commonly bone marrow, but also potentially liver, spleen, lymph nodes, and gastrointestinal tract.
CMS-HCC V28
00
RAF 0
CMS-HCC V24
00
RAF 0
ACA/HHS
00
RAF 0
ESRD/PACE
00
RAF 0
RXHCC
MappedHCC 21
RAF 0.0
Code Trumping
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Code Book Path
Inclusion Terms
Official- Indolent systemic mastocytosis
- Isolated bone marrow mastocytosis
- Smoldering systemic mastocytosis
- Systemic mastocytosis, with an associated hematological non-mast cell lineage disease (SM-AHNMD)
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for D47.02 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for D47.02 in this effective period.
Excludes 1
Official- aggressive systemic mastocytosis (C96.21)
- mast cell leukemia (C94.3-)
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for D47.02 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for D47.02 in this effective period.
Code Also
Official- , if applicable, any associated hematological non-mast cell lineage disease, such as:
- acute myeloid leukemia (C92.6-, C92.A-)
- chronic myelomonocytic leukemia (C93.1-)
- essential thrombocytosis (D47.3)
- hypereosinophilic syndrome (D72.1)
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.
Is D47.02 an HCC code?
No. D47.02 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for D47.02
For D47.02to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.
- 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
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed D47.02 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
D47.02 is the ICD-10-CM diagnosis code for systemic mastocytosis. An abnormal growth of mast cells affecting multiple body systems beyond the skin, potentially involving organs like the bone marrow, liver, or spleen. D47.02 sits in the ICD-10-CM chapter for neoplasms (c00-d49), within the section covering neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes (d37-d48).
D47.02 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.
This code maps only to RxHCC 21 (Lymphoma and Other Cancers). It does not map to HCC V28, V24, or ESRD models. Despite the potentially serious nature of systemic mastocytosis, the HCC impact is limited to the prescription drug model, reflecting the specialized medication needs of these patients.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for D47.02 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure documentation specifies systemic involvement beyond cutaneous manifestations
- •Review bone marrow biopsy or other tissue biopsies confirming mast cell infiltration in multiple sites
Clinical Significance
Systemic mastocytosis is a clonal mast cell disorder involving extracutaneous organs, most commonly bone marrow, but also potentially liver, spleen, lymph nodes, and gastrointestinal tract. It can range from indolent disease requiring minimal intervention to aggressive forms with organ damage, and carries risk of anaphylaxis requiring emergency preparedness.
Documentation Requirements
- ✓Documentation must confirm extracutaneous involvement, typically through bone marrow biopsy showing mast cell aggregates, elevated serum tryptase levels, and KIT D816V mutation testing.
- ✓Organ involvement (hepatosplenomegaly, lymphadenopathy, gastrointestinal symptoms) should be documented.
- ✓Classify as indolent, smoldering, or aggressive based on presence of C-findings (organ damage).
Excludes 1, Do NOT code together
Code Also
- , if applicable, any associated hematological non-mast cell lineage disease, such as:
- acute myeloid leukemia (C92.6-, C92.A-)
- chronic myelomonocytic leukemia (C93.1-)
- essential thrombocytosis (D47.3)
- hypereosinophilic syndrome (D72.1)
- myelodysplastic syndrome (D46.9)
- myeloproliferative syndrome (D47.1)
- non-Hodgkin lymphoma (C82-C85)
- plasma cell myeloma (C90.0-)
- polycythemia vera (D45)
Commonly Confused Codes
- •D47.01 (cutaneous mastocytosis) is limited to skin involvement without systemic disease.
- •D47.09 (other mast cell neoplasms) covers atypical presentations.
- •C96.20 (malignant mast cell neoplasm) is used for mast cell leukemia or mast cell sarcoma, which are distinct from systemic mastocytosis.
- •C96.A (histiocytic sarcoma) is a different mast cell lineage malignancy.