What does ICD-10 code C91.Z mean?

ICD-10 code C91.Z is the standardized code used for other lymphoid leukemia in medical records and coding systems.

When is ICD-10 code C91.Z used?

Doctors, hospitals, and insurers may use ICD-10 code C91.Z when recording other lymphoid leukemia in a standardized format. This entry may also act as a broader category that points toward more specific child codes.

Does ICD-10 code C91.Z confirm a diagnosis?

No. A code helps standardize documentation and claims, but it should not be read as a substitute for a clinician's full assessment.

ICD10

ICD-10 Code C91.Z: Other lymphoid leukemia

Name: ICD-10 Code C91.Z: Other lymphoid leukemia
Creator: HealthAssure Clinical Team
Published: 2026-05-21T06:03:24.629Z

C91.Z is an ICD-10 diagnosis entry used to group records related to Other lymphoid leukemia. You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen. ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Neoplasms (C00-D49).

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Neoplasms (C00-D49).

When is it used?

May be used when a clinician documents other lymphoid leukemia in a patient's medical record.
May appear in hospital records, claims, referrals, and clinical documentation.
This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.

What it does not mean

A code alone does not explain severity, treatment plan, or outcome.
A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
This entry may represent a broader category rather than the most specific billable code.

Code hierarchy

chapter

2Neoplasms (C00-D49)

block

C00-C96Malignant neoplasms

block

C81-C96Malignant neoplasms of lymphoid, hematopoietic and related tissue

Official coding notes

Inclusion terms

T-cell large granular lymphocytic leukemia (associated with rheumatoid arthritis)

Where you may see this code

You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.

Related specialists

OncologistGeneral Physician

Sibling codes

C91.0Acute lymphoblastic leukemia [ALL]C91.1Chronic lymphocytic leukemia of B-cell type C91.3Prolymphocytic leukemia of B-cell type C91.4Hairy cell leukemia C91.5Adult T-cell lymphoma/leukemia (HTLV-1-associated)C91.6Prolymphocytic leukemia of T-cell type C91.AMature B-cell leukemia Burkitt-type C91.9Lymphoid leukemia, unspecified

Coding guidelines

Common synonyms

Other lymphoid leukemia

Frequently asked questions

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.