D57.432
BillableSickle-cell thalassemia beta zero with splenic sequestration
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D57.432 an HCC code?
Yes. D57.432 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 D57.432
For D57.432 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 D57.432 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D57.432 is the ICD-10-CM diagnosis code for sickle-cell thalassemia beta zero with splenic sequestration. This is a serious blood disorder where a person has both sickle cell disease and a form of thalassemia, and their spleen is trapping and destroying blood cells faster than normal. This condition causes the spleen to become enlarged and can lead to severe anemia and other complications. D57.432 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, D57.432 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, D57.432 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.
This code requires documentation of both the sickle-cell thalassemia diagnosis AND the acute splenic sequestration event; do not assign this code if only the sickle-cell thalassemia is present without documented sequestration. Because D57.432 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 D57.432 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code requires documentation of both the sickle-cell thalassemia diagnosis AND the acute splenic sequestration event; do not assign this code if only the sickle-cell thalassemia is present without documented sequestration
- •Splenic sequestration is a medical emergency requiring immediate treatment; verify the clinical documentation clearly states the sequestration episode and ensure this code is not confused with other sickle-cell complications like vaso-occlusive crisis
Clinical Significance
Splenic sequestration in sickle-cell thalassemia beta zero is an acute crisis where the spleen traps blood, causing rapid anemia and potential cardiovascular collapse. Beta-zero patients may undergo autosplenectomy in childhood similar to Hemoglobin SS patients, making this complication more common in younger patients. However, some beta-zero patients retain splenic function longer depending on the specific thalassemia mutation and fetal hemoglobin levels.
Documentation Requirements
- ✓Documentation must confirm sickle-cell thalassemia beta zero genotype and acute splenic sequestration with evidence of rapid splenic enlargement and hemoglobin decline.
- ✓Record splenic size (exam or imaging), hemoglobin trend from baseline, reticulocyte count, platelet count, treatment including transfusion, hemodynamic stability assessment, and whether splenectomy is planned.
Commonly Confused Codes
- •D57.432 vs. D57.412 (Unspecified sickle-cell thalassemia with splenic sequestration) -
- •D57.432 specifies beta-zero. D57.432 vs. D57.452 (Beta plus with splenic sequestration) -
- •beta-plus patients more commonly retain splenic function. D57.432 vs. D57.02 (Hemoglobin SS with splenic sequestration) -
- •clinically similar, genetically distinct.