DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

D81 Combined immunodeficiencies

  • Header · not billable

D81 is not billable. The category heads 17 billable codes in FY2027, grouped under 10 subdivisions.

Index → code

  • Nezelof's syndrome (pure alymphocytosis) → D81.4
  • SyndromeNezelof's → D81.4
  • Syndromebare lymphocyte → D81.6

Where it sits

  1. Chapter 3 Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)
  2. D80-D89 Certain disorders involving the immune mechanism (D80-D89)
  3. D81 Combined immunodeficiencies
Billable codes
17
Subdivisions
10
CC / MCC codes
14 / 0
HCC V28 codes
14
New FY2027
0
Index entries
36

Codes in D81

  1. D81.0
    Severe combined immunodeficiency [SCID] with reticular dysgenesis
    BillableCC114
  2. D81.1
    Severe combined immunodeficiency [SCID] with low T- and B-cell numbers
    BillableCC114
  3. D81.2
    Severe combined immunodeficiency [SCID] with low or normal B-cell numbers
    BillableCC114
  4. D81.3
    Adenosine deaminase [ADA] deficiency
    Header
  5. D81.30
    Adenosine deaminase deficiency, unspecified
    BillableCC114
    Inclusion terms 1

    Inclusion terms

    • ADA deficiency NOS
  6. D81.31
    Severe combined immunodeficiency due to adenosine deaminase deficiency
    BillableCC114
    Inclusion terms 2

    Inclusion terms

    • ADA deficiency with SCID
    • Adenosine deaminase [ADA] deficiency with severe combined immunodeficiency
  7. D81.32
    Adenosine deaminase 2 deficiency
    BillableCC114
    Inclusion terms 2, Code also 3

    Inclusion terms

    • ADA2 deficiency
    • Adenosine deaminase deficiency type 2

    Code also

    • , if applicable, any associated manifestations, such as:
    • polyarteritis nodosa (M30.0) M30.0
    • stroke (I63.-) I63
  8. D81.39
    Other adenosine deaminase deficiency
    BillableCC114
    Inclusion terms 5

    Inclusion terms

    • Adenosine deaminase [ADA] deficiency type 1, NOS
    • Adenosine deaminase [ADA] deficiency type 1, without SCID
    • Adenosine deaminase [ADA] deficiency type 1, without severe combined immunodeficiency
    • Partial ADA deficiency (type 1)
    • Partial adenosine deaminase deficiency (type 1)
  9. D81.4
    Nezelof's syndrome
    BillableCC115
  10. D81.5
    Purine nucleoside phosphorylase [PNP] deficiency
    BillableCC114
  11. D81.6
    Major histocompatibility complex class I deficiency
    BillableCC114
    Inclusion terms 1

    Inclusion terms

    • Bare lymphocyte syndrome
  12. D81.7
    Major histocompatibility complex class II deficiency
    BillableCC114
  13. D81.8
    Other combined immunodeficiencies
    Header
  14. D81.81
    Biotin-dependent carboxylase deficiency
    Header
    Inclusion terms 1, Excludes1 1

    Inclusion terms

    • Multiple carboxylase deficiency

    Excludes1

    • biotin-dependent carboxylase deficiency due to dietary deficiency of biotin (E53.8) E53.8
  15. D81.810
    Biotinidase deficiency
    Billable
  16. D81.818
    Other biotin-dependent carboxylase deficiency
    Billable
    Inclusion terms 2

    Inclusion terms

    • Holocarboxylase synthetase deficiency
    • Other multiple carboxylase deficiency
  17. D81.819
    Biotin-dependent carboxylase deficiency, unspecified
    Billable
    Inclusion terms 1

    Inclusion terms

    • Multiple carboxylase deficiency, unspecified
  18. D81.82
    Activated Phosphoinositide 3-kinase Delta Syndrome [APDS]
    BillableCC114
    Inclusion terms 1, Code also 6

    Inclusion terms

    • p110d-activating mutation causing senescent T cells, lymphadenopathy, and immunodeficiency [PASLI] disease

    Code also

    • , if applicable, any associated manifestations, such as:
    • bronchiectasis (J47.-) J47
    • herpes virus infections (B00.-) B00
    • other acute respiratory tract infections (J00-J06; J20-J22) J00 J06 J20 J22
    • other infections (A00-B99) A00 B99
    • pneumonia (J12-J18) J12 J18
  19. D81.89
    Other combined immunodeficiencies
    BillableCC114
  20. D81.9
    Combined immunodeficiency, unspecified
    BillableCC114
    Inclusion terms 1

    Inclusion terms

    • Severe combined immunodeficiency disorder [SCID] NOS

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 D81

Excludes1

  • autosomal recessive agammaglobulinemia (Swiss type) (D80.0) D80.0

Notes that also apply

Block D80-D89 instructions (Includes 3, Excludes1 2, Excludes2 1): printed on the block page.

Chapter 3 instructions (Excludes2 9): printed on the chapter 3 page.

Index entries

  • Nezelof's syndrome (pure alymphocytosis) → D81.4
  • Deficiency, deficientadenosine deaminase (ADA) → D81.30
  • Deficiency, deficientADA2 (adenosine deaminase 2) → D81.32
  • SyndromeNezelof's → D81.4
  • Deficiency, deficientpurine nucleoside phosphorylase (PNP) → D81.5
  • Syndromebare lymphocyte → D81.6
  • Deficiency, deficientbiotinidase → D81.810
  • Deficiency, deficientbiotin-dependent carboxylase → D81.819
  • Disease, diseasedp110d-activating mutation causing senescent T cells, lymphadenopathy, and immunodeficiency [PASLI] → D81.82
  • Syndromeactivated phosphoinositide 3-kinase delta syndrome [APDS] → D81.82
  • Agammaglobulinemia (acquired (secondary)) (nonfamilial)lymphopenic → D81.9
  • Immunodeficiencycombined → D81.9
  • Immunodeficiencysevere combined (SCID) → D81.9
  • Syndromecombined immunity deficiency → D81.9
  • Syndromeimmunity deficiency, combined → D81.9
  • Immunodeficiencywithadenosine-deaminase deficiency → D81.30
  • Deficiency, deficientadenosine deaminase (ADA)with severe combined immunodeficiency (SCID) → D81.31
  • Immunodeficiencysevere combined (SCID)due to adenosine deaminase deficiency → D81.31
  • Deficiency, deficientadenosine deaminase (ADA)type 2 → D81.32
  • Deficiency, deficientadenosine deaminase (ADA)partial (type 1) → D81.39
  • Deficiency, deficientadenosine deaminase (ADA)specified NEC → D81.39
  • Deficiency, deficientadenosine deaminase (ADA)type 1 (without SCID) (without severe combined immunodeficiency) → D81.39
  • Deficiency, deficientmajor histocompatibility complexclass I → D81.6
  • Deficiency, deficientmajor histocompatibility complexclass II → D81.7
  • Immunodeficiencycombinedbiotin-dependent carboxylase → D81.819
  • Immunodeficiencycombinedspecified type NEC → D81.89
  • Agammaglobulinemia (acquired (secondary)) (nonfamilial)withlymphopenia → D81.9
  • Deficiency, deficientimmunitycombined → D81.9
  • Immunodeficiencycombinedsevere (SCID) → D81.9
  • Syndromeimmunodeficiencycombined → D81.9
  • Immunodeficiencycombinedbiotin-dependent carboxylasebiotinidase → D81.810
  • Immunodeficiencycombinedbiotin-dependent carboxylaseholocarboxylase synthetase → D81.818
  • Immunodeficiencycombinedbiotin-dependent carboxylasespecified type NEC → D81.818
  • Immunodeficiencycombinedsevere (SCID)withreticular dysgenesis → D81.0
  • Immunodeficiencycombinedsevere (SCID)withlow T- and B-cell numbers → D81.1
  • Immunodeficiencycombinedsevere (SCID)withlow or normal B-cell numbers → D81.2

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

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