D84.1 Defects in the complement system
The ICD-10-CM code for Defects in the complement system is D84.1 (FY2026). It is a billable, claim-ready diagnosis code.
Classification
- Section
- D80-D89: Certain disorders involving the immune mechanism (D80-D89)
- Category D84
- 10 codes (7 billable)
- FY2026 Status
- Stable since FY2024
Also Known As
ICD-10-CM Alphabetic Index entries that lead to D84.1:
- Defect, defective › complement system
- Quincke's disease or edema › hereditary
- Deficiency, deficient › C1 esterase inhibitor (C1-INH)
- Bannister's disease › hereditary
- Angioneurotic edema (allergic) (any site) (with urticaria) › hereditary
- Angioedema (allergic) (any site) (with urticaria) › hereditary
- Edema, edematous (infectious) (pitting) (toxic) › circumscribed, acute › hereditary
- Edema, edematous (infectious) (pitting) (toxic) › angioneurotic (allergic) (any site) (with urticaria) › hereditary
Inclusion Terms
- C1 esterase inhibitor [C1-INH] deficiency
U.S. Hospital Utilization
- An estimated 2,660 U.S. inpatient stays in 2023 included D84.1 among the documented diagnoses.
- 775 stays listed it as the principal diagnosis.
Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.
Official Coding Guidelines
Chapter 3 TOC entry3. Chapter 3: Disease of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) ............................................................................................. 39
Reserved for future guideline expansionReserved for future guideline expansion ...................................................................................... 39
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026