2026 ICD-10-CM Diagnosis Code D81Combined immunodeficiencies

ICD-10-CM Codes›D50–D89›D80-D89›D81

ICD-10-CM D81
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D81 is a non-billable ICD-10-CM category code for combined immunodeficiencies, so it cannot be submitted on claims. Use a more specific code from this category instead, such as D81.0, D81.1, D81.2, and D81.30.

Code Identity

ICD-10-CM Code
D81
Billable Status
No — Non-Billable Category
Code Describes
Combined immunodeficiencies
Chapter
D80-D89
Certain disorders involving the immune mechanism

Code Classification

ChapterD50–D89Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
SectionD80-D89Certain disorders involving the immune mechanism
CategoryD81Combined immunodeficiencies
This CodeD81Combined immunodeficiencies

Specific Coding for Combined immunodeficienciesOverview

Non-specific codes like D81 require more characters. Use one of these billable codes instead:

  • Use D81.0 for Severe combined immunodeficiency [SCID] with reticular dysgenesis

  • Use D81.1 for Severe combined immunodeficiency [SCID] with low T- and B-cell numbers

  • Use D81.2 for Severe combined immunodeficiency [SCID] with low or normal B-cell numbers

  • D81.3 for Adenosine deaminase [ADA] deficiency

  • Use D81.30 for Adenosine deaminase deficiency, unspecified

  • Use D81.31 for Severe combined immunodeficiency due to adenosine deaminase deficiency

  • Use D81.32 for Adenosine deaminase 2 deficiency

  • Use D81.39 for Other adenosine deaminase deficiency

  • Use D81.4 for Nezelof's syndrome

  • Use D81.5 for Purine nucleoside phosphorylase [PNP] deficiency

  • Use D81.6 for Major histocompatibility complex class I deficiency

  • Use D81.7 for Major histocompatibility complex class II deficiency

  • D81.8 for Other combined immunodeficiencies

  • D81.81 for Biotin-dependent carboxylase deficiency

  • Use D81.82 for Activated Phosphoinositide 3-kinase Delta Syndrome [APDS]

  • Use D81.89 for Other combined immunodeficiencies

  • Use D81.9 for Combined immunodeficiency, unspecified

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Type 1 Excludes

  • autosomal recessive agammaglobulinemia Swiss type D80.0

Patient EducationClinical

Immune System and Disorders

Your immune system is a complex network of cells, tissues, and organs. Together they help the body fight infections and other diseases.

The full article covers:

  • What is the immune system?
  • What are the parts of the immune system?
  • How does the immune system work?
  • What are the types of immunity?
  • What can go wrong with the immune system?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About D81Overview

Is D81 (Combined immunodeficiencies) a billable code?

No. This is a category header that groups the codes for combined immunodeficiencies, and headers cannot be submitted on claims. Claims for combined immunodeficiencies need a more specific code from this category, such as D81.0, D81.1, and D81.2.