D89.4
⚠ Non-billable (Header)Mast cell activation syndrome and related disorders
Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)
⚠️ This is a category header code — not billable. Use a more specific child code below.
❌ Excludes1
directCannot be coded with D89.4
- • 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)
❌ Excludes1
inherited from D89Rules from parent category D89: Other disorders involving the immune mechanism, not elsewhere classified
- • hyperglobulinemia NOS (R77.1)
- • monoclonal gammopathy (of undetermined significance) (D47.2)
⚠️ Excludes2
inherited from D89Rules from parent category D89: Other disorders involving the immune mechanism, not elsewhere classified
- • transplant failure and rejection (T86.-)
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CodeD89.4
BillableNo — Header code
ParentD89
CategoryDiseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)
Excludes113 rule(s)
Excludes21 note(s)
Child codes6
Data Source
CMS ICD-10-CM 2026 Tabular List
Updated October 1, 2025 (FY2026)