Skip to main content

D89.4 ICD-10-CM Code: Mast cell activation syndrome and related disorders

Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.

Official Registry Overview & Definition

Mast cell activation syndrome and related disorders is a non-billable ICD-10-CM category code (D89.4). A more specific billable subcode must be selected for claims submission.

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for D89.4 in the official ICD-10-CM tabular list.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • defects in the complement system
  • immunodeficiency disorders, except human immunodeficiency virus [HIV] disease
  • sarcoidosis

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Frequently Compared Codes

The official Excludes notes on D89.4 name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

  • FY2027 — 2026-10-01
    Excludes2 note added
    human immunodeficiency virus [HIV] disease (B20)
    FY2027 changes
  • FY2027 — 2026-10-01
    Excludes1 note removed
    human immunodeficiency virus [HIV] disease (B20)
    FY2027 changes
  • FY2017 — 2016-10-01
    Added to the code set
    Mast cell activation syndrome and related disorders
    FY2017 changes

Verify Before Coding

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.

Contextual Map

Every relationship of D89.4 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

  • D50-D89 — Chapter 3: Diseases of the Blood and Blood-forming Organs and Certain Disorders Involving the Immune Mechanism (D50-D89) (D50-D89) [Hierarchy]
  • D80-D89 — Certain disorders involving the immune mechanism [Hierarchy]

Excludes1 (9)

  • C94.3 — Mast cell leukemia [Excludes1]: “mast cell leukemia (C94.3-)” · check together
  • C96.2 — Malignant mast cell neoplasm [Excludes1]: “malignant mast cell neoplasm (C96.2-)” · check together
  • C96.21 — Aggressive systemic mastocytosis [Excludes1]: “aggressive systemic mastocytosis (C96.21)” · check together
  • C96.22 — Mast cell sarcoma [Excludes1]: “mast cell sarcoma (C96.22)” · check together
  • C96.29 — Other malignant mast cell neoplasm [Excludes1]: “malignant mastocytoma (C96.29)” · check together
  • D47.01 — Cutaneous mastocytosis [Excludes1]: “(non-congenital) cutaneous mastocytosis (D47.01)” · check together
  • D47.02 — Systemic mastocytosis [Excludes1]: “(indolent) systemic mastocytosis (D47.02)” · check together
  • D47.09 — Other mast cell neoplasms of uncertain behavior [Excludes1]: “mastocytoma NOS (D47.09)” · check together
  • and 1 more

Nearest codes (28)

  • D89 — Other disorders involving the immune mechanism, not elsewhere classified [Sibling]
  • D89.0 — Polyclonal hypergammaglobulinemia [Sibling]
  • D89.1 — Cryoglobulinemia [Sibling]
  • D89.2 — Hypergammaglobulinemia, unspecified [Sibling]
  • D89.3 — Immune reconstitution syndrome [Sibling]
  • D89.40 — Mast cell activation, unspecified [Sibling]
  • D89.41 — Monoclonal mast cell activation syndrome [Sibling]
  • D89.42 — Idiopathic mast cell activation syndrome [Sibling]
  • and 20 more

Change history (3)

  • FY2027 — Excludes2 note added [Change history]
  • and 2 more

Frequently Asked Questions (FAQ) & Clinical Guidance

Can D89.4 be billed directly?

No. D89.4 (Mast cell activation syndrome and related disorders) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to D89.4 in its code family, with their registry titles.

  • D89 — Other disorders involving the immune mechanism, not elsewhere classified
  • D89.0 — Polyclonal hypergammaglobulinemia
  • D89.1 — Cryoglobulinemia
  • D89.2 — Hypergammaglobulinemia, unspecified
  • D89.3 — Immune reconstitution syndrome
  • D89.40 — Mast cell activation, unspecified
  • D89.41 — Monoclonal mast cell activation syndrome
  • D89.42 — Idiopathic mast cell activation syndrome
  • D89.43 — Secondary mast cell activation
  • D89.44 — Hereditary alpha tryptasemia

View all codes in the D89 family