D57.211
BillableSickle-cell/Hb-C disease with acute chest syndrome
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D57.211 an HCC code?
Yes. D57.211 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 D57.211
For D57.211 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 D57.211 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D57.211 is the ICD-10-CM diagnosis code for sickle-cell/hb-c disease with acute chest syndrome. A blood disorder combining sickle cell disease and hemoglobin C disease that causes a sudden, life-threatening complication affecting the lungs with chest pain and difficulty breathing. D57.211 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, D57.211 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, D57.211 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.
Acute chest syndrome is a serious vaso-occlusive crisis; ensure documentation clearly indicates this acute complication occurred during the encounter. Because D57.211 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 D57.211 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Acute chest syndrome is a serious vaso-occlusive crisis; ensure documentation clearly indicates this acute complication occurred during the encounter
- •This code requires documentation of both the sickle-cell/Hb-C disease AND the acute chest syndrome to be appropriately assigned
Clinical Significance
Acute chest syndrome in sickle-cell/Hemoglobin C disease presents similarly to Hemoglobin SS acute chest syndrome but may be less frequent. It remains a serious, potentially life-threatening complication requiring new pulmonary infiltrate with respiratory symptoms. Hemoglobin SC patients may have a deceptively higher baseline hemoglobin that can mask the severity of acute illness, and hyperviscosity can exacerbate pulmonary complications.
Documentation Requirements
- ✓Documentation must confirm the Hemoglobin SC genotype, the clinical diagnosis of acute chest syndrome with respiratory symptoms (chest pain, dyspnea, fever, hypoxia), and new pulmonary infiltrate on chest imaging. Record oxygen saturation, treatment administered (transfusion or exchange transfusion, antibiotics, oxygen), and clinical course. The provider must explicitly diagnose acute chest syndrome -
- ✓do not infer from imaging alone.