C91.10 — Chronic lymphocytic leukemia of B-cell type not having achieved remission

C91.10

ICD-10 Chapter 2: Neoplasms — illustrative image — Chapter 2: Neoplasms (C00–D49) — illustrative image

What this code means

Chronic lymphocytic leukaemia is a slow-growing cancer of white blood cells, most common in older adults.

Also called: chronic lymphocytic leukemia, cll.

When this code is used

Used for CLL of B-cell type that has not achieved remission.

Where it sits in ICD-10-CM

Code C91.10 belongs to Chapter 2: Neoplasms, which covers codes C00–D49 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.

Learn more about this condition

Condition guide: Cancer

Related symptoms

Fatigue

Frequently asked questions

What is ICD-10-CM code C91.10?

C91.10 is the ICD-10-CM diagnosis code for “Chronic lymphocytic leukemia of B-cell type not having achieved remission”. Chronic lymphocytic leukaemia is a slow-growing cancer of white blood cells, most common in older adults.

When is code C91.10 used?

Used for CLL of B-cell type that has not achieved remission. It belongs to Chapter 2 of ICD-10-CM (Neoplasms).

This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.