D83.9 ICD-10-CM Code: Common variable immunodeficiency, unspecified
D83.9 maps to CMS-HCC V28 114. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · free HCC coding tools
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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)
D83.9
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceCommon variable immunodeficiency, unspecified
A common variable immunodeficiency where the immune system is weakened, but the specific type of immune cell or function problem has not been identified.
Buddy Insight
Common variable immunodeficiency, unspecified, indicates a confirmed diagnosis of common variable immunodeficiency where the specific immunological subtype has not been determined through testing.
CMS-HCC V28
MappedHCC 114
Coefficient HCC 114: 2.262 (Community Non-Dual Aged (CNA))
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 D83.9. 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 D83.9. Check the code and parent instructions in the Code Book.
Use Additional
OfficialNo Use Additional Code instructions are included in this display for D83.9. Check the code and parent instructions in the Code Book.
Code Also
OfficialNo Code Also instructions are included in this display for D83.9. 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 D83.9 an HCC code?
Yes. D83.9 (Common variable immunodeficiency, unspecified) maps to HCC 114, Common Variable and Combined Immunodeficiencies under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 2.262. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.
Coder answer: D83.9 is billable and maps to V28 HCC 114, Common Variable and Combined Immunodeficiencies. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- D83.9
- Description
- Common variable immunodeficiency, unspecified
- HCC (V28)
- HCC 114 — Common Variable and Combined Immunodeficiencies
- RAF reference coefficient
- 2.262
- 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 D83.9 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →
MEAT review for D83.9
For D83.9, 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
D83.9 is the ICD-10-CM diagnosis code for common variable immunodeficiency, unspecified. A common variable immunodeficiency where the immune system is weakened, but the specific type of immune cell or function problem has not been identified. D83.9 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).
Under the CMS-HCC V28 risk adjustment model, D83.9 maps to Common Variable and Combined Immunodeficiencies (HCC 114) with a source-labeled community, non-dual, aged reference coefficient of 2.262. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.
This is a default code for CVID; use only when immunological testing results are unavailable or inconclusive. For D83.9, 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. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for D83.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a default code for CVID; use only when immunological testing results are unavailable or inconclusive
- •Encourage providers to complete immunological workup to assign a more specific D83 code
Clinical Significance
Common variable immunodeficiency, unspecified, indicates a confirmed diagnosis of common variable immunodeficiency where the specific immunological subtype has not been determined through testing. Common variable immunodeficiency is the most frequently diagnosed symptomatic primary immunodeficiency in adults, requiring lifelong immunoglobulin replacement therapy and monitoring for complications including malignancy, autoimmune disease, and granulomatous inflammation.
Documentation Requirements
- ✓Documentation must include at least two immunoglobulin classes significantly below normal for age, poor response to vaccine challenge, exclusion of other causes of hypogammaglobulinemia, and clinical manifestations.
- ✓Document the reason why specific subcategorization (B-cell, T-cell, or autoantibody-mediated) cannot be determined and the plan for further immunological characterization if applicable.
Commonly Confused Codes
- •D83.0 through D83.8 (specific common variable immunodeficiency subtypes that should be used when immunological testing supports categorization), D80.9 (unspecified antibody deficiency which does not meet full CVID diagnostic criteria), D84.9 (immunodeficiency, unspecified, an even less specific code), D81.9 (combined immunodeficiency, unspecified, for primarily cellular defects).