D84.1 — Defects in the complement system
Is D84.1 billable?
Yes — D84.1 is billable for FY2027. D84.1 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. D84.1 may be submitted for encounters from October 1, 2026 through September 30, 2027.
D84.1 at a glance
| Code | D84.1 |
|---|---|
| Description | Defects in the complement system |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does D84.1 group to?
D84.1 sits in MDC 10 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 642Inborn and Other Disorders of Metabolismmedical
How is D84.1 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to D84.1. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Angioedema › hereditary (allergic) (any site) (with urticaria)
- Angioneurotic edema › hereditary (allergic) (any site) (with urticaria)
- Bannister's disease › hereditary
- Defect, defective › complement system
- Deficiency, deficient › C1 esterase inhibitor
- Quincke's disease or edema › hereditary
- Edema, edematous › angioneurotic › hereditary (infectious) (pitting) (toxic)
- Edema, edematous › circumscribed, acute › hereditary (infectious) (pitting) (toxic)
- Edema, edematous › essential, acute › hereditary (infectious) (pitting) (toxic)
- Edema, edematous › periodic › hereditary (infectious) (pitting) (toxic)
- Edema, edematous › Quincke's › hereditary (infectious) (pitting) (toxic)
- Giant › urticaria › hereditary
Inclusion terms
Alternative wording in documentation that is classified to D84.1.
- C1 esterase inhibitor [C1-INH] deficiency
Excludes1 — never code together — inherited from D80-D89
The conditions below can never be reported together with D84.1 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
Excludes2 — not included here — inherited from Chapter 3
The conditions below are not part of D84.1, but a patient may have both at the same time. When documentation supports it, D84.1 and the excluded code may both be reported.
- autoimmune disease (systemic) NOS (M35.9)
- certain conditions originating in the perinatal period (P00-P96)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- human immunodeficiency virus [HIV] disease (B20)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Excludes2 — not included here — inherited from D80-D89
The conditions below are not part of D84.1, but a patient may have both at the same time. When documentation supports it, D84.1 and the excluded code may both be reported.
- human immunodeficiency virus [HIV] disease (B20)
How long has D84.1 existed?
D84.1 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which codes are confused with D84.1?
ICD-10-CM declares these codes mutually exclusive with D84.1 — exactly one of each pair can be correct for a given encounter.