D83.9
BillableCommon variable immunodeficiency, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D83.9 an HCC code?
Yes. D83.9 maps to Severe Combined Immunodeficiency and Other Immune Disorders under the CMS-HCC V28 risk adjustment model (and Disorders of Immunity under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for D83.9
For D83.9 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- 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
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed D83.9 during that encounter — not just copy-forwarded from a problem list.
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 Severe Combined Immunodeficiency and Other Immune Disorders (HCC 114) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, D83.9 maps to Disorders of Immunity (HCC 47) with a community, non-dual, aged base RAF weight of 0.472. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
This is a default code for CVID; use only when immunological testing results are unavailable or inconclusive. Because D83.9 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, 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.