D56.2
BillableDelta-beta thalassemia
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D56.2 an HCC code?
Yes. D56.2 maps to Sickle Cell Disorders and Thalassemia under the CMS-HCC V28 risk adjustment model (and Coagulation Defects and Other Specified Hematological Disorders 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 D56.2
For D56.2 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 D56.2 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D56.2 is the ICD-10-CM diagnosis code for delta-beta thalassemia. Delta-beta thalassemia is a rare inherited blood disorder where the body doesn't make enough hemoglobin, a protein in red blood cells that carries oxygen. This condition affects the production of two types of hemoglobin chains (delta and beta), leading to anemia and related complications. D56.2 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 hemolytic anemias (d55-d59).
Under the CMS-HCC V28 risk adjustment model, D56.2 maps to Sickle Cell Disorders and Thalassemia (HCC 108) with a community, non-dual, aged base RAF weight of 0.607. Under the older CMS-HCC V24 model, D56.2 maps to Coagulation Defects and Other Specified Hematological Disorders (HCC 48) with a community, non-dual, aged base RAF weight of 0.209. 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.
Verify the specific type of thalassemia documented in the medical record, as D56.2 is specifically for delta-beta thalassemia and should not be confused with other thalassemia variants (D56.0, D56.1, D56.3, D56.4, D56.5, or D56.8). Because D56.2 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 D56.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify the specific type of thalassemia documented in the medical record, as D56.2 is specifically for delta-beta thalassemia and should not be confused with other thalassemia variants (D56.0, D56.1, D56.3, D56.4, D56.5, or D56.8)
- •Document any complications such as hemolytic anemia, splenomegaly, or transfusion dependence separately, as these may require additional codes to fully capture the clinical picture and severity
Clinical Significance
Delta-beta thalassemia is a rare inherited hemoglobin disorder caused by deletions affecting both the delta and beta globin genes, resulting in reduced production of both hemoglobin A and hemoglobin A2 with compensatory elevation of fetal hemoglobin. Clinical presentation is generally milder than beta thalassemia major, often resembling thalassemia intermedia with moderate anemia. The elevated fetal hemoglobin provides some clinical benefit by partially compensating for reduced adult hemoglobin production.
Documentation Requirements
- ✓Documentation must confirm delta-beta thalassemia specifically through hemoglobin electrophoresis showing elevated fetal hemoglobin with reduced hemoglobin A and A2, and ideally molecular genetic testing confirming the delta-beta deletion.
- ✓Record hemoglobin levels, mean corpuscular volume, reticulocyte counts, transfusion requirements if any, and complications.
- ✓Distinguish clearly from beta thalassemia and hereditary persistence of fetal hemoglobin.