ICD-10-CM 2027
ICD-10 code for Immunodeficient NOS
From the official ICD-10-CM alphabetic index entry “Immunodeficient NOS”. Page updated September 29, 2026.
About coding Immunodeficient NOS
The ICD-10-CM code for Immunodeficient NOS is D84.9 (Immunodeficiency, unspecified).
Within D84, choose D84.9 (Immunodeficiency, unspecified) only when documentation doesn't support a more specific option: lymphocyte function antigen-1 [LFA-1] defect (D84.0), defects in the complement system (D84.1) and other specified immunodeficiencies (D84.8).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 814 (Reticuloendothelial and Immunity Disorders with MCC, relative weight 2.0729), DRG 815 (Reticuloendothelial and Immunity Disorders with CC, relative weight 1.0444) and DRG 816 (Reticuloendothelial and Immunity Disorders without CC/MCC, relative weight 0.7381), in MDC 16 (Diseases and Disorders of the Blood and Blood Forming Organs and Immunological Disorders), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Immunodeficient NOS ICD-10 codes
What is the ICD-10 code for Immunodeficient NOS?
- D84.9 — Immunodeficiency, unspecified.
Is D84.9 billable?
- Yes. D84.9 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can D84.9 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict D84.9 as a principal diagnosis.
Is D84.9 a CC or MCC?
- D84.9 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.