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D89.40

✓ Billable

Mast cell activation, unspecified

Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)

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Also Known As

Mast cell activation disorder, unspecifiedMast cell activation syndrome, NOS

❌ Excludes1

inherited from D89.4

Rules from parent category D89.4: Mast cell activation syndrome and related disorders

  • • aggressive systemic mastocytosis (C96.21)
  • • congenital cutaneous mastocytosis (Q82.2)
  • • (non-congenital) cutaneous mastocytosis (D47.01)
  • • (indolent) systemic mastocytosis (D47.02)
  • • malignant mast cell neoplasm (C96.2-)
  • • malignant mastocytoma (C96.29)
  • • mast cell leukemia (C94.3-)
  • • mast cell sarcoma (C96.22)
  • • mastocytoma NOS (D47.09)
  • • other mast cell neoplasms of uncertain behavior (D47.09)
  • • systemic mastocytosis associated with a clonal hematologic non-mast cell lineage disease (SM-AHNMD) (D47.02)

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Code Information

CodeD89.40
BillableYes
ParentD89.4
CategoryDiseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)
Excludes111 rule(s)
Excludes20 note(s)

Data Source

CMS ICD-10-CM 2026 Tabular List

Updated October 1, 2025 (FY2026)