D56.1
BillableBeta thalassemia
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D56.1 an HCC code?
Yes. D56.1 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 D56.1
For D56.1 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 D56.1 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D56.1 is the ICD-10-CM diagnosis code for beta thalassemia. A genetic blood disorder where the body cannot make enough beta-globin chains, which are part of hemoglobin. This causes moderate to severe anemia and may require regular blood transfusions. D56.1 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, D56.1 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, D56.1 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.
Specify the type: beta thalassemia major, intermedia, or minor based on clinical severity. Because D56.1 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 D56.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Specify the type: beta thalassemia major, intermedia, or minor based on clinical severity
- •Document transfusion requirements and any complications like iron overload
Clinical Significance
Beta thalassemia results from mutations reducing or eliminating beta-globin chain production, causing ineffective erythropoiesis and hemolytic anemia. Beta thalassemia major (Cooley anemia) is transfusion-dependent from early childhood, while beta thalassemia intermedia presents with moderate anemia that may or may not require transfusions. The condition carries significant morbidity from iron overload, skeletal changes, and organ damage, making it a high-acuity chronic condition.
Documentation Requirements
- ✓Documentation must specify the beta thalassemia subtype (major, intermedia, or minor), supported by hemoglobin electrophoresis, genetic testing, or molecular analysis.
- ✓Record transfusion schedule and frequency, iron chelation therapy, ferritin levels, cardiac and hepatic iron assessment results, and complications including endocrinopathies, osteoporosis, or extramedullary hematopoiesis.
- ✓Annual comprehensive assessment documentation supports recapture.
Excludes 1 — Do NOT code together
Commonly Confused Codes
- •D56.1 vs. D56.0 (Alpha thalassemia) -
- •different globin chain affected. D56.1 vs. D56.5 (Hemoglobin E-beta thalassemia) -
- •D56.5 is for the specific compound heterozygous state with hemoglobin E. D56.1 vs. D57.40 (Sickle-cell thalassemia without crisis) -
- •D57.40 is for co-inheritance of sickle cell and thalassemia genes. D56.1 vs. D56.3 (Thalassemia minor) -
- •use D56.1 for beta thalassemia major and intermedia.