D57.439
BillableSickle-cell thalassemia beta zero with crisis, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is D57.439 an HCC code?
Yes. D57.439 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 D57.439
For D57.439 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 D57.439 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
D57.439 is the ICD-10-CM diagnosis code for sickle-cell thalassemia beta zero with crisis, unspecified. A combination blood disorder with sickle-cell and thalassemia beta-zero that is in crisis, but the specific type or complication of the crisis is not documented. D57.439 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, D57.439 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, D57.439 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 is a default code when crisis is present but no specific complication is identified; query the provider for clarification if possible. Because D57.439 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 D57.439 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is a default code when crisis is present but no specific complication is identified; query the provider for clarification if possible
- •Review concurrent diagnoses to identify potential complications that may have been missed in coding
Clinical Significance
This unspecified crisis code for sickle-cell thalassemia beta zero indicates the patient experienced an acute exacerbation but the specific crisis type was not documented. While the beta-zero genotype is specified (yielding the higher HCC mapping), the crisis type remains a documentation improvement opportunity. The clinical management varies based on the crisis type, making provider specification important for both coding accuracy and optimal patient care.
Documentation Requirements
- ✓Documentation must confirm sickle-cell thalassemia beta zero genotype and that an acute crisis is present at the encounter.
- ✓Query the provider for the specific crisis type (acute chest syndrome, splenic sequestration, cerebral vascular involvement, dactylitis, or other).
- ✓Record pain severity, vital signs, laboratory findings, treatment administered, and clinical course.
Commonly Confused Codes
- •D57.439 vs. D57.431-D57.438 (Beta zero with specific crisis types) -
- •query for specificity to assign the correct crisis code. D57.439 vs. D57.42 (Beta zero without crisis) -
- •D57.42 is for steady state. D57.439 vs. D57.419 (Unspecified thalassemia with unspecified crisis) -
- •D57.439 specifies beta-zero, yielding higher HCC.