D89.4

Non-billable

Mast cell activation syndrome and related disorders

D89.4 is the ICD-10-CM code for Mast cell activation syndrome and related disorders. It is a non-billable category code — use a more specific child code such as D89.40 for billing.

Status
Header (non-billable)
Chapter
D50-D89
Parent
D89
Subcodes
6
Edition
FY2026

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

Excludes1 — not coded here

  • 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)

Frequently asked questions

What is ICD-10 code D89.4?
D89.4 is the ICD-10-CM code for "Mast cell activation syndrome and related disorders". It falls under D50-D89 Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism.
Is D89.4 a billable code?
No — D89.4 is a non-billable header code. Use a more specific child code (such as D89.40) for billing.
What are the subcodes of D89.4?
D89.4 has 6 more specific child codes, including D89.40, D89.41, D89.42.
What is excluded from D89.4?
Excludes1 (not coded here): aggressive systemic mastocytosis (C96.21); congenital cutaneous mastocytosis (Q82.2); (non-congenital) cutaneous mastocytosis (D47.01); (indolent) systemic mastocytosis (D47.02).

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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