D89.9 is the authoritative medical code for Disorder involving the immune mechanism, unspecified. This classification is used in medical billing and clinical recording to specify the clinical criteria for disorder involving the immune mechanism, unspecified (ICD-10-CM D89.9), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Official Registry Overview & Definition
Disorder involving the immune mechanism, unspecified is a billable ICD-10-CM diagnosis code D89.9. Includes: defects in the complement system; immunodeficiency disorders, except human immunodeficiency virus HIV disease; sarcoidosis. Inclusion terms: Immune disease NOS. Excludes1 (not coded here): hyperglobulinemia NOS R77.1; monoclonal gammopathy (of undetermined significance) D47.2; autoimmune disease systemic NOS M35.9; functional disorders of polymorphonuclear neutrophils D71-; human immunodeficiency virus HIV disease B20. Excludes2 (not included here): transplant failure and rejection T86.-.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for D89.9 in the official ICD-10-CM tabular list.
Includes
Conditions the official ICD-10-CM tabular list includes under this code.
- defects in the complement system
- immunodeficiency disorders, except human immunodeficiency virus HIV disease
- sarcoidosis
Inclusion Terms
Alternative terms the tabular list files under this code.
Excludes1 — Not Coded Here
Conditions that can never be reported with this code; the two are mutually exclusive.
- hyperglobulinemia NOS R77.1
- monoclonal gammopathy (of undetermined significance) D47.2
- autoimmune disease systemic NOS M35.9
- functional disorders of polymorphonuclear neutrophils D71-
- human immunodeficiency virus HIV disease B20
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- transplant failure and rejection T86.-
Frequently Asked Questions (FAQ) & Clinical Guidance
What can't be coded together with D89.9?
Per Excludes1 instructions, D89.9 must not be reported with: hyperglobulinemia NOS (R77.1); monoclonal gammopathy (of undetermined significance) (D47.2); autoimmune disease (systemic) NOS (M35.9); functional disorders of polymorphonuclear neutrophils (D71-).
Can D89.9 be reported alongside related conditions?
Per Excludes2 instructions, D89.9 and the following may both be reported when both are present: transplant failure and rejection (T86.-).
What conditions are included under D89.9?
Disorder involving the immune mechanism, unspecified includes: Immune disease NOS.
Codes in This Family (17)
Official ICD-10-CM classifications in the same code family as D89.9, with their registry titles.
- D89 — Other disorders involving the immune mechanism, not elsewhere classified
- D89.0 — Polyclonal hypergammaglobulinemia
- D89.1 — Cryoglobulinemia
- D89.2 — Hypergammaglobulinemia, unspecified
- D89.3 — Immune reconstitution syndrome
- D89.4 — Mast cell activation syndrome and related disorders
- D89.8 — Other specified disorders involving the immune mechanism, not elsewhere classified
- D89.810 — Acute graft-versus-host disease
- D89.811 — Chronic graft-versus-host disease
- D89.812 — Acute on chronic graft-versus-host disease
- D89.813 — Graft-versus-host disease, unspecified
- D89.831 — Cytokine release syndrome, grade 1
- D89.832 — Cytokine release syndrome, grade 2
- D89.833 — Cytokine release syndrome, grade 3
- D89.834 — Cytokine release syndrome, grade 4
- D89.835 — Cytokine release syndrome, grade 5
- D89.839 — Cytokine release syndrome, grade unspecified
Indexed Clinical Terms (2)
Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.
- Disease, diseased, immune
- Disorder (of), immune mechanism (immunity)
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures: