Non-Billable / Non-Specific Code
ICD-10-CM D89.4 is the diagnosis code for Mast cell activation syndrome and related disorders. This code falls under the section "Certain disorders involving the immune mechanism" within Chapter 3 — Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as D89.4. They are mutually exclusive:
Understanding where D89.4 sits in the ICD-10-CM classification helps ensure proper coding:
No, D89.4 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
D89.4 is the ICD-10-CM diagnosis code for "Mast cell activation syndrome and related disorders". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
The parent code of D89.4 is D89 ("Other disorders involving the immune mechanism, not elsewhere classified"). D89.4 provides a more specific classification within this category.
D89.4 is located in Section D80-D89 — "Certain disorders involving the immune mechanism" within Chapter 3 of the ICD-10-CM Tabular List.
D89.4 has 6 sub-code(s) that provide more specific detail: D89.40, D89.41, D89.42, D89.43, D89.44 and more.
Use D89.4 when the patients documented diagnosis matches "Mast cell activation syndrome and related disorders" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Mast cell activation syndrome and related disorders is D89.4.
No, D89.4 is non-billable. Use a more specific sub-code for primary diagnosis billing.
D89.4 is in Chapter 3 of the ICD-10-CM Tabular List.
Type 1 Excludes for D89.4 include: aggressive systemic mastocytosis (C96.21); congenital cutaneous mastocytosis (Q82.2); (non-congenital) cutaneous mastocytosis (D47.01) and more.
Yes, D89.4 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.