Coding and coverage · ICD-10-CM
Instructional notes
Chapter 3
Excludes2Not included here: the patient may have both; report both when both are present.
- autoimmune disease (systemic) NOS (M35.9)
- certain conditions originating in the perinatal period (P00-P96)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- human immunodeficiency virus [HIV] disease (B20)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Section D80-D89
Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
Excludes2Not included here: the patient may have both; report both when both are present.
- human immunodeficiency virus [HIV] disease (B20)
Includes
- defects in the complement system
- immunodeficiency disorders, except human immunodeficiency virus [HIV] disease
- sarcoidosis
D89
Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
Excludes2Not included here: the patient may have both; report both when both are present.
- transplant failure and rejection (T86.-)
D89.4
Excludes1Not coded here: never report with this code, except when the two conditions are unrelated.
- 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)
This code
Code also
- underlying etiology, if known
Inclusion terms
- Secondary mast cell activation syndrome
Chapter 3: Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism · D80-D89 Certain disorders involving the immune mechanism (D80-D89)
Source: ICD-10-CM FY 2027 code descriptions and tabular list (CMS and CDC National Center for Health Statistics), effective 2026-10-01 through 2027-09-30 · CMS ICD-10 files. HCC mapping: CMS-HCC V28, payment year 2027. As of 2026-11-04.
Coverage and payment depend on the claim details; confirm with the Medicare Administrative Contractor.