C91.00 – Acute lymphoblastic leukemia not having achieved remission

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

Billable code

ICD-10-CM code C91.00

Code: C91.00 (claims format: C9100)
Description: Acute lymphoblastic leukemia not having achieved remission
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 › C91.0

Notes for C91.00

Applicable to:

Acute lymphoblastic leukemia with failed remission
Acute lymphoblastic leukemia NOS

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)

C91.0 – Acute lymphoblastic leukemia [ALL]

Notes:

Codes in subcategory C91.0- should only be used for T-cell and B-cell precursor leukemia

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 C91.0

Frequently asked questions

What is ICD-10 code C91.00?

C91.00 is the ICD-10-CM code for acute lymphoblastic leukemia not having achieved remission, in the block C81-C96 (Malignant neoplasms of lymphoid, hematopoietic and related tissue).

Is C91.00 a billable code?

Yes. C91.00 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does C91.00 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.