D81.9 – Combined immunodeficiency, unspecified
ICD-10-CM 2027 diagnosis code · Certain disorders involving the immune mechanism
ICD-10-CM code
D81.9
- Code
D81.9(claims format:D819)- Description
- Combined immunodeficiency, unspecified
- Billable
- Yes – valid for HIPAA-covered transactions
- Valid for
- Dates of service October 1, 2026 – September 30, 2027 (FY2027)
- Chapter
- 3. Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)
- Block
- D80-D89 Certain disorders involving the immune mechanism
- Parent codes
- D81
Notes for D81.9
Applicable to:
- Severe combined immunodeficiency disorder [SCID] NOS
Notes inherited from parent codes
Instructional notes at a category or block level apply to every code below it.
D81 – Combined immunodeficiencies
Excludes1 (not coded here):
- autosomal recessive agammaglobulinemia (Swiss type) (D80.0)
Block D80-D89
Includes:
- defects in the complement system
- immunodeficiency disorders, except human immunodeficiency virus [HIV] disease
- sarcoidosis
Excludes1 (not coded here):
Excludes2 (not included here):
- human immunodeficiency virus [HIV] disease (B20)
Index terms for D81.9
Entries in the ICD-10-CM alphabetic index that lead to this code:
- Immunodeficiency, combined
- Agammaglobulinemia, lymphopenic
- Immunodeficiency, severe combined
- Immunodeficiency, combined, severe
- Syndrome, immunodeficiency, combined
- Agammaglobulinemia, with, lymphopenia
- Syndrome, combined immunity deficiency
- Syndrome, immunity deficiency, combined
- Deficiency, deficient, immunity, combined
Related codes in D81
- D81.0 – Severe combined immunodeficiency [SCID] with reticular dysgenesisBillable
- D81.1 – Severe combined immunodeficiency [SCID] with low T- and B-cell numbersBillable
- D81.2 – Severe combined immunodeficiency [SCID] with low or normal B-cell numbersBillable
- D81.3 – Adenosine deaminase [ADA] deficiencyHeader
- D81.4 – Nezelof's syndromeBillable
- D81.5 – Purine nucleoside phosphorylase [PNP] deficiencyBillable
- D81.6 – Major histocompatibility complex class I deficiencyBillable
- D81.7 – Major histocompatibility complex class II deficiencyBillable
- D81.8 – Other combined immunodeficienciesHeader
Frequently asked questions
What is ICD-10 code D81.9?
D81.9 is the ICD-10-CM code for combined immunodeficiency, unspecified, in the block D80-D89 (Certain disorders involving the immune mechanism).
Is D81.9 a billable code?
Yes. D81.9 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.
What category does D81.9 belong to?
It belongs to category D81 – Combined immunodeficiencies.
Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.