ICD-10 Code C91.31 – Prolymphocytic leukemia of B-cell type, in remission (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C91.31 – Prolymphocytic leukemia of B-cell type, in remission
What it is
This code identifies a history of B-cell prolymphocytic leukemia that is currently in remission. Use it when the record shows the disease is no longer active, but the diagnosis remains clinically relevant.
Clinical signs
Clinical features vary; refer to documentation. Standard references describe B-cell prolymphocytic leukemia as an uncommon mature B-cell leukemia that may present with lymphocytosis, splenomegaly, and systemic symptoms before remission is documented.
When to use this code
Use C91.31 when the provider documents B-cell prolymphocytic leukemia as being in remission, including follow-up visits after treatment. It is appropriate when the encounter is for surveillance, history review, or ongoing oncology management and not for active disease. Check documentation if remission status is unclear.
Do not use for
Do not use this code for active B-cell prolymphocytic leukemia, relapsed disease, or cases where the type is not specified. If the note only says leukemia without remission status, check documentation.
Coding tip
Confirm both the B-cell type and remission status in the provider note before assigning C91.31.