D84.89 ICD-10-CM Code: Other immunodeficiencies
D84.89 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools
HCC Buddy Code Card
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FY 2026 Apr update / Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) / Certain disorders involving the immune mechanism (D80-D89)
D84.89
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceOther immunodeficiencies
This code represents rare or unusual immune system disorders that don't fit into other specific immunodeficiency categories. These conditions affect the body's ability to fight infections and diseases.
Buddy Insight
Other immunodeficiencies represents a category for documented immunodeficiency disorders that do not fit into the specifically defined categories within the D80-D84 classification system.
CMS-HCC V28
N/A—
Not mapped
CMS-HCC V24
HistoricalHistorical
Not used for CY2026 payment
ACA/HHS
MappedHCC 074
Code-level coefficient reference
ESRD/PACE
MappedHCC 47
Code-level coefficient reference
RXHCC
MappedHCC 99
Code-level coefficient reference
Code Book Path
Inclusion Terms
OfficialNo inclusion terms are included in this display for D84.89. Check the code and parent instructions in the Code Book.
Excludes 2
Official- autoimmune disease (systemic) NOS (M35.9)Inherited from D50-D89
- certain conditions originating in the perinatal period (P00-P96)Inherited from D50-D89
- complications of pregnancy, childbirth and the puerperium (O00-O9A)Inherited from D50-D89
- congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)Inherited from D50-D89
- endocrine, nutritional and metabolic diseases (E00-E88)Inherited from D50-D89
- human immunodeficiency virus [HIV] disease (B20)Inherited from D50-D89
- injury, poisoning and certain other consequences of external causes (S00-T88)Inherited from D50-D89
- neoplasms (C00-D49)Inherited from D50-D89
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)Inherited from D50-D89
Related Codes
Includes
Official- defects in the complement systemInherited from D80-D89
- immunodeficiency disorders, except human immunodeficiency virus [HIV] diseaseInherited from D80-D89
- sarcoidosisInherited from D80-D89
Excludes 1
Official- autoimmune disease (systemic) NOS (M35.9)Inherited from D80-D89
- functional disorders of polymorphonuclear neutrophils (D71-)Inherited from D80-D89
- human immunodeficiency virus [HIV] disease (B20)Inherited from D80-D89
Code First
OfficialNo Code First sequencing instructions are included in this display for D84.89. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for D84.89. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for D84.89. Check the code and parent instructions in the Code Book.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is D84.89 an HCC code?
D84.89 is not in the CMS-HCC V28 or V24 community payment model. D84.89 has a separate mapping under the CMS-HCC ESRD model (HCC 47 (Disorders of Immunity)) and the Part D RxHCC model (HCC 99 (Immune Disorders)); the applicable result needs member context. D84.89 also appears in the HHS-HCC commercial risk model (HCC 074 (HHS-HCC 074 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping.
- Code
- D84.89
- Description
- Other immunodeficiencies
- HCC (V28)
- No CMS-HCC V28 mapping
- RAF reference coefficient
- —
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.
Work D84.89 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for D84.89
For D84.89, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Coder workflow notes
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What This Code Means
D84.89 is the ICD-10-CM diagnosis code for other immunodeficiencies. This code represents rare or unusual immune system disorders that don't fit into other specific immunodeficiency categories. These conditions affect the body's ability to fight infections and diseases. D84.89 sits in the ICD-10-CM chapter for diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (d50-d89), within the section covering certain disorders involving the immune mechanism (d80-d89).
D84.89 has no mapping under the CMS-HCC V28 or V24 community payment models. D84.89 has a separate mapping under the CMS-HCC ESRD model (HCC 47 (Disorders of Immunity)) and the Part D RxHCC model (HCC 99 (Immune Disorders)); the applicable result needs member context. D84.89 also appears in the HHS-HCC commercial risk model (HCC 074 (HHS-HCC 074 adult, RAF varies by metal level)), which is a commercial market model rather than a Medicare Advantage payment mapping. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.
Use this code only after confirming that the immunodeficiency doesn't meet criteria for more specific codes like D84.0-D84.8, as this is a catch-all category.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for D84.89 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only after confirming that the immunodeficiency doesn't meet criteria for more specific codes like D84.0-D84.8, as this is a catch-all category
- •Always document the specific type of immunodeficiency in the medical record and consider querying the provider if the condition seems more specific, as this code may trigger audits due to its non-specific nature
Clinical Significance
Other immunodeficiencies represents a category for documented immunodeficiency disorders that do not fit into the specifically defined categories within the D80-D84 classification system. This includes rare or emerging immunodeficiency conditions, atypical presentations, or conditions where the specific mechanism is identified but lacks a dedicated ICD-10-CM code.
Documentation Requirements
- ✓Documentation must specify the particular immunodeficiency identified, include immunological testing results supporting the diagnosis, clinical manifestations, and the rationale for why the condition does not fit other D80-D84 subcategories.
- ✓Document the specific immune defect, affected cell populations or pathways, and treatment approach.
Commonly Confused Codes
- •D84.9 (immunodeficiency, unspecified, used when the type is completely unknown), D84.81 (immunodeficiency due to conditions classified elsewhere for secondary causes), D84.821 (immunodeficiency due to drugs), D81.89 (other combined immunodeficiencies which specifically involves both T-cell and B-cell defects), D80.8 (other antibody deficiencies for primarily humoral defects).