ICD-10 Code C94.30 – Mast cell leukemia not having achieved remission (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C94.30 – Mast cell leukemia not having achieved remission
What it is
This code identifies mast cell leukemia that remains active and has not entered remission. Use it when the record specifically documents this diagnosis and the disease is still present.
Clinical signs
Clinical features vary; refer to documentation. Standard references describe an aggressive mast cell neoplasm with systemic involvement, and patients may have findings consistent with advanced hematologic disease.
When to use this code
Use this code when the provider documents mast cell leukemia and also states that remission has not been achieved. It is appropriate for active disease during evaluation, ongoing management, or restaging when the condition is still present. Check documentation if the record only says “mast cell disease” or “mastocytosis.”
Do not use for
Do not use this code for mast cell leukemia in remission or when remission status is not documented. Do not assign it for other mast cell disorders unless the provider clearly identifies mast cell leukemia.
Coding tip
Code the remission status exactly as documented; if the chart is unclear, query the provider before assigning C94.30.