D89.42

Idiopathic mast cell activation syndrome

Billable / specific

D89.42 is a billable, specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes in FY2027.

Inclusion terms

Not coded here — never report together with this code.

aggressive systemic mastocytosis (C96.21) (from D89.4)
congenital cutaneous mastocytosis (Q82.2) (from D89.4)
(non-congenital) cutaneous mastocytosis (D47.01) (from D89.4)
(indolent) systemic mastocytosis (D47.02) (from D89.4)
malignant mast cell neoplasm (C96.2-) (from D89.4)
malignant mastocytoma (C96.29) (from D89.4)
mast cell leukemia (C94.3-) (from D89.4)
mast cell sarcoma (C96.22) (from D89.4)
mastocytoma NOS (D47.09) (from D89.4)
other mast cell neoplasms of uncertain behavior (D47.09) (from D89.4)
systemic mastocytosis associated with a clonal hematologic non-mast cell lineage disease (SM-AHNMD) (D47.02) (from D89.4)
autoimmune disease (systemic) NOS (M35.9) (from D89)
functional disorders of polymorphonuclear neutrophils (D71-) (from D89)
hyperglobulinemia NOS (R77.1) (from D89)
monoclonal gammopathy (of undetermined significance) (D47.2) (from D89)

Not included here — may be reported together when both conditions exist.

autoimmune disease (systemic) NOS (M35.9) (from D89)
certain conditions originating in the perinatal period (P00-P96) (from D89)
complications of pregnancy, childbirth and the puerperium (O00-O9A) (from D89)
congenital malformations, deformations and chromosomal abnormalities (Q00-Q99) (from D89)
endocrine, nutritional and metabolic diseases (E00-E88) (from D89)
human immunodeficiency virus [HIV] disease (B20) (from D89)
injury, poisoning and certain other consequences of external causes (S00-T88) (from D89)
neoplasms (C00-D49) (from D89)
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94) (from D89)
human immunodeficiency virus [HIV] disease (B20) (from D89)
transplant failure and rejection (T86.-) (from D89)