Mast cell leukemia not having achieved remission

This code describes a rare, aggressive hematologic malignancy characterized by the uncontrolled proliferation of neoplastic mast cells in the bone marrow, peripheral blood, and often other organs. It signifies that the patient's mast cell leukemia is currently active and has not responded to treatment sufficiently to be considered in remission.

Use this code for patients diagnosed with mast cell leukemia who are actively undergoing treatment, have relapsed, or whose disease has not achieved a state of remission following therapy. Documentation must clearly state a diagnosis of mast cell leukemia and indicate that remission has not been attained.

• Distinguish from C94.31 (mast cell leukemia, in remission) based on the patient's current disease status.
• Always sequence this code as the primary diagnosis when it is the reason for the encounter.
• Ensure the medical record explicitly documents "not in remission" or similar language to support this specific code.