D89.41 (Monoclonal mast cell activation syndrome) compared with T86 (Complications of transplanted organs and tissue), from the official CMS tabular data. Both may be reported when both conditions are documented (Excludes2).
Distinct conditions — both may be reported.
“transplant failure and rejection (T86.-)”
An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.
Source: CMS ICD-10-CM tabular instructional notes
Yes, when both are documented. D89.41 carries an Excludes2 note covering T86: “transplant failure and rejection (T86.-)”
Excludes2 marks distinct conditions — both may be reported when both are documented.
| D89.41Monoclonal mast cell activation syndrome | T86Complications of transplanted organs and tissue | |
|---|---|---|
| Billing status | Billable | Non-billable header |
| Classification | D50-D89 — Diseases of the Blood and Blood-forming Organs and Certain Disorders Involving the Immune Mechanism (D50-D89) | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) |
| Definition | Monoclonal mast cell activation syndrome is a billable ICD-10-CM diagnosis code (D89.41). | Complications of transplanted organs and tissue is a non-billable ICD-10-CM category code (T86). |
| Includes | defects in the complement system immunodeficiency disorders, except human immunodeficiency virus [HIV] disease sarcoidosis | — |
| Use additional code | — | code to identify other transplant complications, such as: graft-versus-host disease (D89.81-) malignancy associated with organ transplant (C80.2) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources