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D89.40 vs T86

D89.40 (Mast cell activation, unspecified) 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).

Can these codes be reported together?

Yes, when both are documented. D89.40 carries an Excludes2 note covering T86: “transplant failure and rejection (T86.-)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

Side by side

D89.40Mast cell activation, unspecifiedT86Complications of transplanted organs and tissue
Billing statusBillableNon-billable header

Report instead: T86.00, T86.01, T86.02, T86.03, T86.09

ClassificationD50-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)
DefinitionMast cell activation, unspecified is a billable ICD-10-CM diagnosis code (D89.40).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
Mast cell activation disorder, unspecified
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