D89.41 — Monoclonal mast cell activation syndrome
Is D89.41 billable?
Yes — D89.41 is billable for FY2027. D89.41 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. D89.41 may be submitted for encounters from October 1, 2026 through September 30, 2027.
D89.41 at a glance
| Code | D89.41 |
|---|---|
| Description | Monoclonal mast cell activation syndrome |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does D89.41 group to?
D89.41 sits in MDC 16 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 814Reticuloendothelial and Immunity Disorders with MCCmedical
- 815Reticuloendothelial and Immunity Disorders with CCmedical
- 816Reticuloendothelial and Immunity Disorders without CC/MCCmedical
How is D89.41 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to D89.41. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Activation › mast cell › monoclonal
Excludes1 — never code together — inherited from D80-D89
The conditions below can never be reported together with D89.41 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes1 — never code together — inherited from D89
The conditions below can never be reported together with D89.41 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes1 — never code together — inherited from D89.4
The conditions below can never be reported together with D89.41 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- 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)
Excludes2 — not included here — inherited from Chapter 3
The conditions below are not part of D89.41, but a patient may have both at the same time. When documentation supports it, D89.41 and the excluded code may both be reported.
- 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)
Excludes2 — not included here — inherited from D80-D89
The conditions below are not part of D89.41, but a patient may have both at the same time. When documentation supports it, D89.41 and the excluded code may both be reported.
- human immunodeficiency virus [HIV] disease (B20)
Excludes2 — not included here — inherited from D89
The conditions below are not part of D89.41, but a patient may have both at the same time. When documentation supports it, D89.41 and the excluded code may both be reported.
- transplant failure and rejection (T86.-)
How long has D89.41 existed?
D89.41 first appears in FY2018 (FY2017 is not available, so it may have appeared then).
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.