2026 ICD-10-CM Diagnosis Code D84.81Immunodeficiency due to conditions classified elsewhere
ICD-10-CM Codes›D50–D89›D80-D89›D84
- Billable — Valid for Submission
- Chronic Condition
D84.81 is a billable ICD-10-CM diagnosis code for immunodeficiency due to conditions classified elsewhere. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 814 through 816. The code is a manifestation code that cannot be reported as the principal diagnosis. Coders also document this condition as immunodeficiency associated with chromosomal abnormality. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Immunity disorders.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for D84.81.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Immunodeficiency associated with chromosomal abnormality
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Code First
- underlying condition, such as:
- chromosomal abnormalities Q90 Q99
- diabetes mellitus E08 E13
- malignant neoplasms C00 C96
Type 1 Excludes
- certain disorders involving the immune mechanism D80 D83 D84.0 D84.1 D84.9
- human immunodeficiency virus HIV disease B20
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
- due to
- conditions classified elsewhere - D84.81
External Cause of Injuries IndexGuidance
References for this code in the External Cause of Injuries Index.
- Immunodeficiency
- due to
- conditions classified elsewhere
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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 History & ChangesHistory
Replacement D84.81 replaces the following previously assigned code(s):
- D84.8 - Other specified immunodeficiencies
Questions About D84.81Overview
Is D84.81 (Other specified immunodeficiencies) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report immunodeficiency due to conditions classified elsewhere on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does D84.81 group to?
On inpatient claims, immunodeficiency due to conditions classified elsewhere maps to MS-DRG 814, 815, 816, with relative weights from 0.6320 to 2.1267 depending on complications. Higher weights mean higher Medicare reimbursement.
Can D84.81 be a principal diagnosis?
No. This is a manifestation code: immunodeficiency due to conditions classified elsewhere describes the manifestation of an underlying disease rather than the disease itself, so the underlying condition is sequenced first.
Footnotes
[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:
- The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
- The condition places limitations on self-care, independent living, and social interactions.
