C96.21

Billable

Aggressive systemic mastocytosis

C96.21 is the ICD-10-CM code for Aggressive systemic mastocytosis. It is a billable, specific code valid for reimbursement.

Status
Billable
Chapter
C00-D49
Parent
C96.2
Edition
FY2026

C00-D49 Neoplasms

What this means — in plain language

MedlinePlus · NIH

Systemic mastocytosis is a blood disorder that can affect many different body systems. Individuals with the condition can develop signs and symptoms at any age, but it usually appears after adolescence. Signs and symptoms of systemic mastocytosis often include extreme tiredness (fatigue), skin redness and warmth (flushing), nausea, abdominal pain, bloating, diarrhea, the backflow of stomach acids into the esophagus…

Read more about Systemic mastocytosis at MedlinePlus ↗

Source: U.S. National Library of Medicine (MedlinePlus). Informational only — not medical advice.

No additional coding notes for this code.

Medications indicated for this condition

FDA labeling

Drugs whose FDA labeling lists this condition's category among its indications. Informational only — not a treatment recommendation or medical advice.

Frequently asked questions

What is ICD-10 code C96.21?
C96.21 is the ICD-10-CM code for "Aggressive systemic mastocytosis". It falls under C00-D49 Neoplasms.
Is C96.21 a billable code?
Yes — C96.21 is a billable, specific ICD-10-CM code valid for reimbursement.

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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