C91.12 – Chronic lymphocytic leukemia of B-cell type in relapse

ICD-10-CM 2027 diagnosis code · Malignant neoplasms of lymphoid, hematopoietic and related tissue

Billable code

ICD-10-CM code C91.12

Code: C91.12 (claims format: C9112)
Description: Chronic lymphocytic leukemia of B-cell type in relapse
Billable: Yes – valid for HIPAA-covered transactions
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 2. Neoplasms (C00-D49)
Block: C81-C96 Malignant neoplasms of lymphoid, hematopoietic and related tissue
Parent codes: C91 › C91.1

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

C91 – Lymphoid leukemia

Excludes1 (not coded here):

personal history of leukemia (Z85.6)

C91.1 – Chronic lymphocytic leukemia of B-cell type

Applicable to:

Lymphoplasmacytic leukemia
Richter syndrome

Excludes1 (not coded here):

lymphoplasmacytic lymphoma (C83.0-)

Block C81-C96

Excludes2 (not included here):

Kaposi's sarcoma of lymph nodes (C46.3)
secondary and unspecified neoplasm of lymph nodes (C77.-)
secondary neoplasm of bone marrow (C79.52)
secondary neoplasm of spleen (C78.89)

Related codes in C91.1

Frequently asked questions

What is ICD-10 code C91.12?

C91.12 is the ICD-10-CM code for chronic lymphocytic leukemia of B-cell type in relapse, in the block C81-C96 (Malignant neoplasms of lymphoid, hematopoietic and related tissue).

Is C91.12 a billable code?

Yes. C91.12 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does C91.12 belong to?

It belongs to category C91 – Lymphoid leukemia.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.