D57.433
BillableSickle-cell thalassemia beta zero with cerebral vascular involvement
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D57.433 an HCC code?
Yes. D57.433 maps to Sickle Cell Anemia (Hb-SS) and Thalassemia Beta Zero under the CMS-HCC V28 risk adjustment model (and Severe 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 D57.433
For D57.433 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 D57.433 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D57.433 is the ICD-10-CM diagnosis code for sickle-cell thalassemia beta zero with cerebral vascular involvement. A combination blood disorder with sickle-cell and thalassemia beta-zero that affects blood vessels in the brain, potentially causing stroke or transient ischemic attack. D57.433 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, D57.433 maps to Sickle Cell Anemia (Hb-SS) and Thalassemia Beta Zero (HCC 107) with a community, non-dual, aged base RAF weight of 0.727. Under the older CMS-HCC V24 model, D57.433 maps to Severe Hematological Disorders (HCC 46) with a community, non-dual, aged base RAF weight of 0.666. 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 evidence of cerebrovascular involvement such as imaging results (CT/MRI), neurological deficits, or stroke diagnosis. Because D57.433 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 D57.433 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document evidence of cerebrovascular involvement such as imaging results (CT/MRI), neurological deficits, or stroke diagnosis
- •Coordinate with neurology documentation to ensure the cerebrovascular event is clearly attributed to the sickle-cell thalassemia condition
Clinical Significance
Cerebral vascular involvement in sickle-cell thalassemia beta zero carries stroke risk equivalent to Hemoglobin SS disease due to the identical clinical phenotype. These patients require the same transcranial Doppler screening, stroke prevention protocols with chronic transfusion therapy, and acute stroke management as Hemoglobin SS patients. The neurological devastation from sickle cell-related stroke makes this one of the most clinically consequential codes in the sickle cell spectrum.
Documentation Requirements
- ✓Documentation must confirm sickle-cell thalassemia beta zero genotype and the cerebrovascular event with neurological examination and neuroimaging.
- ✓Record the stroke type (ischemic, hemorrhagic, transient ischemic attack, or silent cerebral infarct), neurological deficits, transcranial Doppler velocity results, treatment (emergency exchange transfusion, chronic transfusion protocol), and neurological rehabilitation plan.
Code Also
- , if applicable cerebral infarction (I63.-)