D57.413
BillableSickle-cell thalassemia, unspecified, with cerebral vascular involvement
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D57.413 an HCC code?
Yes. D57.413 maps to Sickle Cell Disorders and Thalassemia 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 D57.413
For D57.413 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 D57.413 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D57.413 is the ICD-10-CM diagnosis code for sickle-cell thalassemia, unspecified, with cerebral vascular involvement. A blood disorder combining sickle cell disease with thalassemia that causes a stroke or other serious blood vessel problems in the brain. D57.413 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, D57.413 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, D57.413 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 the specific cerebral vascular event and coordinate with imaging and neurology documentation. Because D57.413 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 D57.413 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Document the specific cerebral vascular event and coordinate with imaging and neurology documentation
- •Ensure the cerebral involvement is acute and related to the sickle-cell thalassemia crisis
Clinical Significance
Cerebral vascular involvement in unspecified sickle-cell thalassemia represents stroke or other cerebrovascular complications in patients with combined sickle cell and thalassemia genes where the specific thalassemia type is not documented. Stroke risk varies by thalassemia subtype -- beta-zero patients have risk similar to Hemoglobin SS, while beta-plus patients generally have lower stroke risk. This underscores the importance of documenting the specific thalassemia type.
Documentation Requirements
- ✓Documentation must confirm the sickle-cell thalassemia genotype and the cerebrovascular event with neurological examination and neuroimaging.
- ✓Query for beta-zero vs.
- ✓beta-plus specification.
- ✓Record the type of cerebrovascular event, neurological deficits, treatment (exchange transfusion protocol), and follow-up plan including chronic transfusion therapy and neurological surveillance.
Code Also
- , if applicable cerebral infarction (I63.-)