ICD-10-CM category
C91: Lymphoid leukemia
Codes under C91 (Lymphoid leukemia). A ✓ marks a billable (fully specified) code; category codes without a ✓ are not billable on their own.
| Code | Description | Billable |
|---|---|---|
| C91.0 | Acute lymphoblastic leukemia [ALL] | — |
| C91.0 | Acute lymphoblastic leukemia [ALL] | — |
| C91.00 | Acute lymphoblastic leukemia not having achieved remission | ✓ |
| C91.00 | Acute lymphoblastic leukemia not having achieved remission | ✓ |
| C91.01 | Acute lymphoblastic leukemia, in remission | ✓ |
| C91.01 | Acute lymphoblastic leukemia, in remission | ✓ |
| C91.1 | Chronic lymphocytic leukemia of B-cell type | — |
| C91.1 | Chronic lymphocytic leukemia of B-cell type | — |
| C91.02 | Acute lymphoblastic leukemia, in relapse | ✓ |
| C91.02 | Acute lymphoblastic leukemia, in relapse | ✓ |
| C91.3 | Prolymphocytic leukemia of B-cell type | — |
| C91.3 | Prolymphocytic leukemia of B-cell type | — |
| C91.4 | Hairy cell leukemia | — |
| C91.4 | Hairy cell leukemia | — |
| C91.5 | Adult T-cell lymphoma/leukemia (HTLV-1-associated) | — |
| C91.5 | Adult T-cell lymphoma/leukemia (HTLV-1-associated) | — |
| C91.6 | Prolymphocytic leukemia of T-cell type | — |
| C91.6 | Prolymphocytic leukemia of T-cell type | — |
| C91.9 | Lymphoid leukemia, unspecified | — |
| C91.9 | Lymphoid leukemia, unspecified | — |
| C91.10 | Chronic lymphocytic leukemia of B-cell type not having achieved remission | ✓ |
| C91.10 | Chronic lymphocytic leukemia of B-cell type not having achieved remission | ✓ |
| C91.11 | Chronic lymphocytic leukemia of B-cell type in remission | ✓ |
| C91.11 | Chronic lymphocytic leukemia of B-cell type in remission | ✓ |
| C91.12 | Chronic lymphocytic leukemia of B-cell type in relapse | ✓ |
| C91.12 | Chronic lymphocytic leukemia of B-cell type in relapse | ✓ |
| C91.30 | Prolymphocytic leukemia of B-cell type not having achieved remission | ✓ |
| C91.30 | Prolymphocytic leukemia of B-cell type not having achieved remission | ✓ |
| C91.31 | Prolymphocytic leukemia of B-cell type, in remission | ✓ |
| C91.31 | Prolymphocytic leukemia of B-cell type, in remission | ✓ |
| C91.32 | Prolymphocytic leukemia of B-cell type, in relapse | ✓ |
| C91.32 | Prolymphocytic leukemia of B-cell type, in relapse | ✓ |
| C91.40 | Hairy cell leukemia not having achieved remission | ✓ |
| C91.40 | Hairy cell leukemia not having achieved remission | ✓ |
| C91.41 | Hairy cell leukemia, in remission | ✓ |
| C91.41 | Hairy cell leukemia, in remission | ✓ |
| C91.42 | Hairy cell leukemia, in relapse | ✓ |
| C91.42 | Hairy cell leukemia, in relapse | ✓ |
| C91.50 | Adult T-cell lymphoma/leukemia (HTLV-1-associated) not having achieved remission | ✓ |
| 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 | ✓ |
| C91.51 | Adult T-cell lymphoma/leukemia (HTLV-1-associated), in remission | ✓ |
| C91.52 | Adult T-cell lymphoma/leukemia (HTLV-1-associated), in relapse | ✓ |
| C91.52 | Adult T-cell lymphoma/leukemia (HTLV-1-associated), in relapse | ✓ |
| C91.60 | Prolymphocytic leukemia of T-cell type not having achieved remission | ✓ |
| C91.60 | Prolymphocytic leukemia of T-cell type not having achieved remission | ✓ |
| C91.61 | Prolymphocytic leukemia of T-cell type, in remission | ✓ |
| C91.61 | Prolymphocytic leukemia of T-cell type, in remission | ✓ |
| C91.62 | Prolymphocytic leukemia of T-cell type, in relapse | ✓ |
| C91.62 | Prolymphocytic leukemia of T-cell type, in relapse | ✓ |
| C91.90 | Lymphoid leukemia, unspecified not having achieved remission | ✓ |
| C91.90 | Lymphoid leukemia, unspecified not having achieved remission | ✓ |
| C91.91 | Lymphoid leukemia, unspecified, in remission | ✓ |
| C91.91 | Lymphoid leukemia, unspecified, in remission | ✓ |
| C91.92 | Lymphoid leukemia, unspecified, in relapse | ✓ |
| C91.92 | Lymphoid leukemia, unspecified, in relapse | ✓ |
| C91.A | Mature B-cell leukemia Burkitt-type | — |
| C91.A | Mature B-cell leukemia Burkitt-type | — |
| C91.A0 | Mature B-cell leukemia Burkitt-type not having achieved remission | ✓ |
| C91.A0 | Mature B-cell leukemia Burkitt-type not having achieved remission | ✓ |
| C91.A1 | Mature B-cell leukemia Burkitt-type, in remission | ✓ |
| C91.A1 | Mature B-cell leukemia Burkitt-type, in remission | ✓ |
| C91.A2 | Mature B-cell leukemia Burkitt-type, in relapse | ✓ |
| C91.A2 | Mature B-cell leukemia Burkitt-type, in relapse | ✓ |
| C91.Z | Other lymphoid leukemia | — |
| C91.Z | Other lymphoid leukemia | — |
| C91.Z0 | Other lymphoid leukemia not having achieved remission | ✓ |
| C91.Z0 | Other lymphoid leukemia not having achieved remission | ✓ |
| C91.Z1 | Other lymphoid leukemia, in remission | ✓ |
| C91.Z1 | Other lymphoid leukemia, in remission | ✓ |
| C91.Z2 | Other lymphoid leukemia, in relapse | ✓ |
| C91.Z2 | Other lymphoid leukemia, in relapse | ✓ |
Frequently asked questions
What is ICD-10-CM code C91?
C91 is an ICD-10-CM category covering Lymphoid leukemia. It contains 72 more specific diagnosis codes, 54 of which are billable.
Is C91 a billable code?
No — C91 is a category header and isn't billable on its own. Code to the highest level of specificity using one of its subcodes (for example C91.0 — Acute lymphoblastic leukemia [ALL]). 54 of the 72 codes under C91 are billable.
What codes fall under C91?
C91 includes C91.0, C91.0, C91.00, C91.00, C91.01, plus 67 more. See the full list with descriptions and billable status above.
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Informational only, not coding or medical advice. Verify against the official ICD-10-CM (FY2026) and your payer's guidelines.
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