D57.431
BillableSickle-cell thalassemia beta zero with acute chest syndrome
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D57.431 an HCC code?
Yes. D57.431 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 D57.431
For D57.431 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 D57.431 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D57.431 is the ICD-10-CM diagnosis code for sickle-cell thalassemia beta zero with acute chest syndrome. A combination blood disorder with sickle-cell and thalassemia beta-zero that causes acute chest syndrome, a serious lung complication with chest pain and breathing difficulty. D57.431 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, D57.431 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, D57.431 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 medical emergency; ensure documentation clearly describes respiratory symptoms, chest pain, and imaging findings. Because D57.431 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 D57.431 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 medical emergency; ensure documentation clearly describes respiratory symptoms, chest pain, and imaging findings
- •Verify beta-zero thalassemia is specifically documented; beta-plus thalassemia uses code D57.451 for the same complication
Clinical Significance
Acute chest syndrome in sickle-cell thalassemia beta zero carries the same life-threatening risk as in Hemoglobin SS disease because the beta-zero genotype produces a clinically equivalent phenotype. These patients develop new pulmonary infiltrates with respiratory symptoms and may deteriorate rapidly, requiring exchange transfusion and intensive care. The recognition of beta-zero status is important because management intensity mirrors Hemoglobin SS protocols.
Documentation Requirements
- ✓Documentation must confirm sickle-cell thalassemia beta zero genotype and the explicit diagnosis of acute chest syndrome with new pulmonary infiltrate and respiratory symptoms. Record oxygen saturation, arterial blood gas values, chest imaging findings, treatment (exchange transfusion targeting Hemoglobin S <30%, antibiotics, respiratory support), and clinical course. The provider must document 'acute chest syndrome' -
- ✓do not infer from imaging.