D56.5
BillableHemoglobin E-beta thalassemia
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D56.5 an HCC code?
Yes. D56.5 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 D56.5
For D56.5 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 D56.5 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D56.5 is the ICD-10-CM diagnosis code for hemoglobin e-beta thalassemia. A blood disorder where a person inherits hemoglobin E from one parent and a thalassemia gene from the other, causing mild to moderate anemia and abnormal red blood cells. D56.5 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, D56.5 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, D56.5 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.
Document whether the patient has hemoglobin E trait or disease to ensure accurate code selection. Because D56.5 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 D56.5 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document whether the patient has hemoglobin E trait or disease to ensure accurate code selection
- •Verify the specific type of beta thalassemia component (thalassemia major, minor, or intermedia) when documented
Clinical Significance
Hemoglobin E-beta thalassemia is a compound heterozygous condition where one parent contributes a hemoglobin E gene and the other a beta thalassemia gene. It is the most common form of severe thalassemia worldwide, particularly prevalent in Southeast Asian populations. Clinical severity varies from asymptomatic to transfusion-dependent, depending on the beta thalassemia mutation type (beta-zero vs. beta-plus), making accurate characterization essential for management planning.
Documentation Requirements
- ✓Document the compound heterozygous state with hemoglobin electrophoresis showing hemoglobin E and elevated fetal hemoglobin, supported by genetic testing when available.
- ✓Specify clinical severity (mild, moderate, or severe/transfusion-dependent), hemoglobin levels, mean corpuscular volume, transfusion schedule, iron chelation therapy, and ferritin monitoring results.
- ✓Record complications including splenomegaly, iron overload, and endocrinopathies.