DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

C91 Lymphoid leukemia

  • Header · not billable

C91 is not billable. The category heads 27 billable codes in FY2027, grouped under 9 subdivisions.

Index → code

  • Burkittcell leukemia → C91.0-
  • Leukemia, leukemiclymphoid → C91.9-
  • Leukemia, leukemichairy cell → C91.4-

Where it sits

  1. Chapter 2 Neoplasms (C00-D49)
  2. C81-C96 Malignant neoplasms of lymphoid, hematopoietic and related tissue (C81-C96)
  3. C91 Lymphoid leukemia
Billable codes
27
Subdivisions
9
CC / MCC codes
27 / 0
HCC V28 codes
27
New FY2027
0
Index entries
17

Codes in C91

  1. C91.0
    Acute lymphoblastic leukemia [ALL]
    Header
    Notes 1

    Notes

    • Codes in subcategory C91.0- should only be used for T-cell and B-cell precursor leukemia C91.0
  2. C91.00
    Acute lymphoblastic leukemia not having achieved remission
    BillableCC18
    Inclusion terms 2

    Inclusion terms

    • Acute lymphoblastic leukemia with failed remission
    • Acute lymphoblastic leukemia NOS
  3. C91.01
    Acute lymphoblastic leukemia, in remission
    BillableCC18
  4. C91.02
    Acute lymphoblastic leukemia, in relapse
    BillableCC18
  5. C91.1
    Chronic lymphocytic leukemia of B-cell type
    Header
    Inclusion terms 2, Excludes1 1

    Inclusion terms

    • Lymphoplasmacytic leukemia
    • Richter syndrome

    Excludes1

    • lymphoplasmacytic lymphoma (C83.0-) C83.0
  6. C91.10
    Chronic lymphocytic leukemia of B-cell type not having achieved remission
    BillableCC22
    Inclusion terms 2

    Inclusion terms

    • Chronic lymphocytic leukemia of B-cell type with failed remission
    • Chronic lymphocytic leukemia of B-cell type NOS
  7. C91.11
    Chronic lymphocytic leukemia of B-cell type in remission
    BillableCC22
  8. C91.12
    Chronic lymphocytic leukemia of B-cell type in relapse
    BillableCC22
  9. C91.3
    Prolymphocytic leukemia of B-cell type
    Header
  10. C91.30
    Prolymphocytic leukemia of B-cell type not having achieved remission
    BillableCC19
    Inclusion terms 2

    Inclusion terms

    • Prolymphocytic leukemia of B-cell type with failed remission
    • Prolymphocytic leukemia of B-cell type NOS
  11. C91.31
    Prolymphocytic leukemia of B-cell type, in remission
    BillableCC19
  12. C91.32
    Prolymphocytic leukemia of B-cell type, in relapse
    BillableCC19
  13. C91.4
    Hairy cell leukemia
    Header
    Inclusion terms 1

    Inclusion terms

    • Leukemic reticuloendotheliosis
  14. C91.40
    Hairy cell leukemia not having achieved remission
    BillableCC22
    Inclusion terms 2

    Inclusion terms

    • Hairy cell leukemia with failed remission
    • Hairy cell leukemia NOS
  15. C91.41
    Hairy cell leukemia, in remission
    BillableCC22
  16. C91.42
    Hairy cell leukemia, in relapse
    BillableCC22
  17. C91.5
    Adult T-cell lymphoma/leukemia (HTLV-1-associated)
    Header
    Inclusion terms 4

    Inclusion terms

    • Acute variant of adult T-cell lymphoma/leukemia (HTLV-1-associated)
    • Chronic variant of adult T-cell lymphoma/leukemia (HTLV-1-associated)
    • Lymphomatoid variant of adult T-cell lymphoma/leukemia (HTLV-1-associated)
    • Smouldering variant of adult T-cell lymphoma/leukemia (HTLV-1-associated)
  18. C91.50
    Adult T-cell lymphoma/leukemia (HTLV-1-associated) not having achieved remission
    BillableCC19
    Inclusion terms 2

    Inclusion terms

    • Adult T-cell lymphoma/leukemia (HTLV-1-associated) with failed remission
    • Adult T-cell lymphoma/leukemia (HTLV-1-associated) NOS
  19. C91.51
    Adult T-cell lymphoma/leukemia (HTLV-1-associated), in remission
    BillableCC19
  20. C91.52
    Adult T-cell lymphoma/leukemia (HTLV-1-associated), in relapse
    BillableCC19
  21. C91.6
    Prolymphocytic leukemia of T-cell type
    Header
  22. C91.60
    Prolymphocytic leukemia of T-cell type not having achieved remission
    BillableCC19
    Inclusion terms 2

    Inclusion terms

    • Prolymphocytic leukemia of T-cell type with failed remission
    • Prolymphocytic leukemia of T-cell type NOS
  23. C91.61
    Prolymphocytic leukemia of T-cell type, in remission
    BillableCC19
  24. C91.62
    Prolymphocytic leukemia of T-cell type, in relapse
    BillableCC19
  25. C91.A
    Mature B-cell leukemia Burkitt-type
    Header
    Excludes1 1

    Excludes1

    • Burkitt lymphoma (C83.7-) C83.7
  26. C91.A0
    Mature B-cell leukemia Burkitt-type not having achieved remission
    BillableCC20
    Inclusion terms 2

    Inclusion terms

    • Mature B-cell leukemia Burkitt-type with failed remission
    • Mature B-cell leukemia Burkitt-type NOS
  27. C91.A1
    Mature B-cell leukemia Burkitt-type, in remission
    BillableCC20
  28. C91.A2
    Mature B-cell leukemia Burkitt-type, in relapse
    BillableCC20
  29. C91.Z
    Other lymphoid leukemia
    Header
    Inclusion terms 1

    Inclusion terms

    • T-cell large granular lymphocytic leukemia (associated with rheumatoid arthritis)
  30. C91.Z0
    Other lymphoid leukemia not having achieved remission
    BillableCC22
    Inclusion terms 2

    Inclusion terms

    • Other lymphoid leukemia with failed remission
    • Other lymphoid leukemia NOS
  31. C91.Z1
    Other lymphoid leukemia, in remission
    BillableCC22
  32. C91.Z2
    Other lymphoid leukemia, in relapse
    BillableCC22
  33. C91.9
    Lymphoid leukemia, unspecified
    Header
  34. C91.90
    Lymphoid leukemia, unspecified not having achieved remission
    BillableCC22
    Inclusion terms 2

    Inclusion terms

    • Lymphoid leukemia with failed remission
    • Lymphoid leukemia NOS
  35. C91.91
    Lymphoid leukemia, unspecified, in remission
    BillableCC22
  36. C91.92
    Lymphoid leukemia, unspecified, in relapse
    BillableCC22

CC/MCC: as a secondary diagnosis, unless the principal diagnosis is on the code’s PDX exclusion list (MS-DRG v44 Appendix C; list on the code card).

Sources of each column.

Instructions

At C91

Excludes1

  • personal history of leukemia (Z85.6) Z85.6

Notes that also apply

Block C81-C96 instructions (Excludes2 4): printed on the block page.

Chapter 2 instructions (Notes 8): printed on the chapter 2 page.

Index entries

  • Burkittcell leukemia → C91.0-
  • Leukemia, leukemicacute lymphoblastic → C91.0-
  • Leukemia, leukemicchronic lymphocytic, of B-cell type → C91.1-
  • Leukemia, leukemichairy cell → C91.4-
  • Reticuloendotheliosisleukemic → C91.4-
  • Leukemia, leukemicadult T-cell (HTLV-1-associated) (acute variant) (chronic variant) (lymphomatoid variant) (smouldering variant) → C91.5-
  • Lymphoma (of) (malignant)adult T-cell (HTLV-1-associated) (acute variant) (chronic variant) (lymphomatoid variant) (smouldering variant) → C91.5-
  • Leukemia, leukemicBurkitt-type, mature B-cell → C91.A-
  • Leukemia, leukemicmature B-cell, Burkitt-type → C91.A-
  • Leukemia, leukemicT-cell large granular lymphocytic → C91.Z-
  • Infiltrate, infiltrationlymphatic → C91.9-
  • Leukemia, leukemiclymphoid → C91.9-
  • Leukemia, leukemicsubacute lymphocytic → C91.9-
  • Burkitttypeacute lymphoblastic leukemia → C91.0-
  • Leukemia, leukemicprolymphocyticof B-cell type → C91.3-
  • Leukemia, leukemicprolymphocyticof T-cell type → C91.6-
  • Leukemia, leukemiclymphoidspecified NEC → C91.Z-

NCHS Alphabetic Index. Index first, then the Tabular List.

Hierarchy