What does ICD-10 code D81 mean?

ICD-10 code D81 is the standardized code used for combined immunodeficiencies in medical records and coding systems.

When is ICD-10 code D81 used?

Doctors, hospitals, and insurers may use ICD-10 code D81 when recording combined immunodeficiencies in a standardized format. This entry may also act as a broader category that points toward more specific child codes.

Does ICD-10 code D81 confirm a diagnosis?

No. A code helps standardize documentation and claims, but it should not be read as a substitute for a clinician's full assessment.

ICD10

ICD-10 Code D81: Combined immunodeficiencies

Name: ICD-10 Code D81: Combined immunodeficiencies
Creator: HealthAssure Clinical Team
Published: 2026-05-21T06:04:36.033Z

D81 is an ICD-10 diagnosis entry used to group records related to Combined immunodeficiencies. You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen. ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89).

Reviewed by HealthAssure Clinical TeamUpdated 21 May 2026

What is this code?

ICD-10 entries help standardize how diagnoses are organized for coding, reporting, analytics, and documentation. This code sits within the broader ICD-10 area for Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89).

When is it used?

May be used when a clinician documents combined immunodeficiencies in a patient's medical record.
May appear in hospital records, claims, referrals, and clinical documentation.
This code may act more like a grouping or parent code, so a more specific child code may be used in final documentation when available.

What it does not mean

A code alone does not explain severity, treatment plan, or outcome.
A medical code should not be treated as a substitute for a doctor's diagnosis or advice.
This entry may represent a broader category rather than the most specific billable code.

Code hierarchy

chapter

3Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89)

block

D80-D89Certain disorders involving the immune mechanism

currentD80-D89

Official coding notes

Excludes1 (do not code together)

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

Where you may see this code

You may see this entry in coding references, medical records, or claims workflows when a broader diagnosis category is being reviewed before a more specific code is chosen.

Related specialists

HematologistGeneral Physician

Sibling codes

D80Immunodeficiency with predominantly antibody defects D82Immunodeficiency associated with other major defects D83Common variable immunodeficiency D84Other immunodeficiencies D86Sarcoidosis D89Other disorders involving the immune mechanism, not elsewhere classified

Coding guidelines

Compatibility

Legacy code aligns to an official FY 2026 category. Frontend should resolve to the official category page and surface the billable child codes.

Legacy codes

D81

Replacement codes

D81.0 — Severe combined immunodeficiency [SCID] with reticular dysgenesisD81.1 — Severe combined immunodeficiency [SCID] with low T- and B-cell numbersD81.2 — Severe combined immunodeficiency [SCID] with low or normal B-cell numbersD81.4 — Nezelof's syndromeD81.5 — Purine nucleoside phosphorylase [PNP] deficiencyD81.6 — Major histocompatibility complex class I deficiencyD81.7 — Major histocompatibility complex class II deficiencyD81.9 — Combined immunodeficiency, unspecified

Common synonyms

Combined immunodeficiencies

Frequently asked questions

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.