2026 ICD-10-CM Diagnosis Code D84.0Lymphocyte function antigen-1 [LFA-1] defect

ICD-10-CM Codes›D50–D89›D80-D89›D84

ICD-10-CM D84.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D84.0 is a billable ICD-10-CM diagnosis code for lymphocyte function antigen-1 [LFA-1] defect. 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. Coders also document this condition as lymphocyte function antigen-1 defect. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Immunity disorders.

Code Identity

ICD-10-CM Code
D84.0
Billable Status
Yes — Valid for Submission
Code Describes
Lymphocyte function antigen-1 [LFA-1] defect
Short Description
Lymphocyte function antigen-1 [LFA-1] defect
Same as the full description in the CMS dataset.
Parent Code
D84
Other immunodeficiencies

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
CategoryD84Other immunodeficiencies
This CodeD84.0Lymphocyte function antigen-1 [LFA-1] defect

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Lymphocyte function antigen-1 defect

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Defect, defective
      • lymphocyte function antigen-1 (LFA-1)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR BLD008
Immunity disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

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.

Convert D84.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
279.8 Immune mechanism dis NEC
Approximate The match is approximate rather than exact.

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 D84.0Overview

Is D84.0 (Other immunodeficiencies) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report lymphocyte function antigen-1 [LFA-1] defect on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does D84.0 group to?

When lymphocyte function antigen-1 [LFA-1] defect is the principal diagnosis on an inpatient stay, it groups to MS-DRG 814, 815, 816, with relative weights from 0.6320 to 2.1267 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of D84.0?

Under the General Equivalence Mappings, lymphocyte function antigen-1 [LFA-1] defect converts to ICD-9-CM 279.8 (immune mechanism dis NEC). The mapping is approximate, so confirm the match fits the documentation.

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.