ICD-10 Code C94.31 – Mast cell leukemia, in remission (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C94.31 – Mast cell leukemia, in remission
What it is
C94.31 identifies a documented history of mast cell leukemia that is currently in remission. Use it when the disease is not active, but the diagnosis remains clinically relevant.
Clinical signs
Clinical features vary; refer to documentation. Active mast cell leukemia may involve abnormal mast cell proliferation and systemic symptoms, but this code applies when remission is specifically stated.
When to use this code
Use this code when the record clearly states mast cell leukemia is in remission, including follow-up visits or survivorship care. It may also support problem lists when the oncologist documents remission status. If remission is not documented, check documentation.
Do not use for
Do not use it for active mast cell leukemia or for a suspected diagnosis without confirmation. Do not assign it if the chart only says “history of” unless remission is explicitly documented.
Coding tip
Match the code to the exact remission wording in the provider note, not to treatment history alone.