D89.9
Billable codeDisorder involving the immune mechanism, unspecified
The ICD-10 code for disorder involving the immune mechanism, unspecified is D89.9.
Clinical notes
Also known as
Alternate wording, synonyms, or specific conditions that fall under this code, listed to help confirm you've picked the right one.
- Immune disease NOS
Documentation support
General coding-documentation guidance — not a substitute for payer-specific requirements or professional coding judgment.
- •This code describes an unspecified presentation. If the medical record documents a more specific detail (e.g. laterality, type, or affected site), a more specific sibling code should be used instead — see Related codes below.
- •As a general rule, code to the highest level of specificity supported by the documentation in the medical record.
Related codes in this category
- D89.0Polyclonal hypergammaglobulinemia
- D89.1Cryoglobulinemia
- D89.2Hypergammaglobulinemia, unspecified
- D89.3Immune reconstitution syndrome
- D89.4Mast cell activation syndrome and related disordersnon-billable header
- D89.8Other specified disorders involving the immune mechanism, not elsewhere classifiednon-billable header
- D89.9Disorder involving the immune mechanism, unspecified
ICD-9-CM equivalent
Informational only — GEM mappings are approximate, not guaranteed one-to-one equivalents. Verify before use in billing.
- 2799
Associated MS-DRGs
D89.9 can serve as the principal diagnosis for these Medicare Severity Diagnosis-Related Groups.
Informational only — actual DRG assignment also depends on procedures, complications/comorbidities (CC/MCC), discharge status, and payer-specific rules not reflected here.