Lymphoid leukemia (C91) ICD-10-CM
The C91 code range covers lymphoid leukemia with 37 ICD-10-CM diagnosis codes. 27 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
- personal history of leukemia Z85.6
Codes in the C91 Range 37 codes · 27 billable
- C91 Lymphoid leukemiaNon-billable
- C91.0 Acute lymphoblastic leukemia [ALL]Non-billable
- C91.00 Acute lymphoblastic leukemia not having achieved remission
- C91.01 Acute lymphoblastic leukemia, in remission
- C91.02 Acute lymphoblastic leukemia, in relapse
- C91.1 Chronic lymphocytic leukemia of B-cell typeNon-billable
- C91.10 Chronic lymphocytic leukemia of B-cell type not having achieved remission
- C91.11 Chronic lymphocytic leukemia of B-cell type in remission
- C91.12 Chronic lymphocytic leukemia of B-cell type in relapse
- C91.3 Prolymphocytic leukemia of B-cell typeNon-billable
- C91.30 Prolymphocytic leukemia of B-cell type not having achieved remission
- C91.31 Prolymphocytic leukemia of B-cell type, in remission
- C91.32 Prolymphocytic leukemia of B-cell type, in relapse
- C91.4 Hairy cell leukemiaNon-billable
- C91.40 Hairy cell leukemia not having achieved remission
- C91.41 Hairy cell leukemia, in remission
- C91.42 Hairy cell leukemia, in relapse
- C91.5 Adult T-cell lymphoma/leukemia (HTLV-1-associated)Non-billable
- C91.50 Adult T-cell lymphoma/leukemia (HTLV-1-associated) not having achieved remission
- C91.51 Adult T-cell lymphoma/leukemia (HTLV-1-associated), in remission
- C91.52 Adult T-cell lymphoma/leukemia (HTLV-1-associated), in relapse
- C91.6 Prolymphocytic leukemia of T-cell typeNon-billable
- C91.60 Prolymphocytic leukemia of T-cell type not having achieved remission
- C91.61 Prolymphocytic leukemia of T-cell type, in remission
- C91.62 Prolymphocytic leukemia of T-cell type, in relapse
- C91.9 Lymphoid leukemia, unspecifiedNon-billable
- C91.90 Lymphoid leukemia, unspecified not having achieved remission
- C91.91 Lymphoid leukemia, unspecified, in remission
- C91.92 Lymphoid leukemia, unspecified, in relapse
- C91.A Mature B-cell leukemia Burkitt-typeNon-billable
- C91.A0 Mature B-cell leukemia Burkitt-type not having achieved remission
- C91.A1 Mature B-cell leukemia Burkitt-type, in remission
- C91.A2 Mature B-cell leukemia Burkitt-type, in relapse
- C91.Z Other lymphoid leukemiaNon-billable
- C91.Z0 Other lymphoid leukemia not having achieved remission
- C91.Z1 Other lymphoid leukemia, in remission
- C91.Z2 Other lymphoid leukemia, in relapse
About the C91 Code Range
The ICD-10 code section C91 is used specifically for diagnosing various types of lymphoid leukemia, a cancer of the white blood cells affecting lymphoid cell lines. This section includes detailed codes for specific forms such as acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia, and other variants, capturing their remission or relapse status.
This section helps medical coders accurately identify the exact type and stage of lymphoid leukemia. For instance, the code C91.0 refers to acute lymphoblastic leukemia, known by synonyms like B-cell acute lymphoblastic leukemia and T-lymphoblastic leukemia. Subcategories like C91.00 specify ALL not yet in remission, important for treatment tracking. Chronic lymphocytic leukemia of B-cell type is identified with C91.1, with related codes marking remission (C91.11) or relapse (C91.12). Other subtypes include hairy cell leukemia (C91.4) and adult T-cell lymphoma/leukemia (C91.5), with synonyms aiding in resolving clinical terminology. This detailed classification allows clinicians and coders to distinguish closely related leukemias and their clinical states using the ICD-10 codes for lymphoid leukemia.
Questions About This Page
How many billable codes are in the C91 range?
Of the 37 codes in this range, 27 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the C91 range classify?
The range classifies lymphoid leukemia. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
