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

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from C91 Lymphoid leukemia

Excludes1 (never code together)

• personal history of leukemia (Z85.6)

Applies from C91.1 Chronic lymphocytic leukemia of B-cell type

Applicable to

• Lymphoplasmacytic leukemia
• Richter syndrome

Excludes1 (never code together)

• lymphoplasmacytic lymphoma (C83.0-)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 22 — Bladder, Colorectal, and Other Cancers
• CMS-HCC V22: HCC 10 — Lymphoma and Other Cancers
• RxHCC V08: HCC 19 — Leukemias and Other Hematologic Cancers
• ESRD V24: HCC 10

MS-DRG index

Defines the logic of DRG(s) 820-822 in MDC 17.

Approximate ICD-9-CM (GEMs)

• 204.12 Chronic lymphoid leukemia, in relapse

Code annotations containing back-references to C91.12

Back-references to C91.1

• Type 1 Excludes: C83.0 Small cell B-cell lymphoma ("chronic lymphocytic leukemia (C91.1)")
• Type 1 Excludes: C84.Z Other mature T/NK-cell lymphomas ("T-cell leukemia (C91.1-)")

Back-references to C91

• Type 1 Excludes: C76 Malignant neoplasm of other and ill-defined sites ("malignant neoplasm of lymphoid, hematopoietic and related tissue (C81-C96)")
• Type 1 Excludes: D72.8 Other specified disorders of white blood cells ("leukemia (C91-C95)")
• Type 1 Excludes: D72.825 Bandemia ("leukemia (C91.-, C92.-, C93.-, C94.-, C95.-)")
• Code First: M36.1 Arthropathy in neoplastic disease ("leukemia (C91-C95)")
• Code First: N16 Renal tubulo-interstitial disorders in diseases classified elsewhere ("leukemia (C91-C95)")
• Code First: R50.81 Fever presenting with conditions classified elsewhere ("leukemia (C91-C95)")
• Type 1 Excludes: T66 Radiation sickness, unspecified ("leukemia (C91-C95)")
• Code First: Z15.0 Genetic susceptibility to malignant neoplasm (", if applicable, any current malignant neoplasm (C00-C75, C81-C96)")

Nearby codes

• C91.01 Acute lymphoblastic leukemia, in remission
• C91.02 Acute lymphoblastic leukemia, in relapse
• C91.1 Chronic lymphocytic leukemia of B-cell type
• 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 (this code)
• C91.3 Prolymphocytic leukemia of B-cell type
• 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 leukemia