D57.451 ICD-10-CM Code: Sickle-cell thalassemia beta plus with acute chest syndrome
D57.451 maps to CMS-HCC V28 108 (RAF 0.146). Documentation must support MEAT. MEAT criteria · RAF calculator · HCC coding software
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FY 2026 Apr update / Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism (D50-D89) / Hemolytic anemias (D55-D59)
D57.451
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceSickle-cell thalassemia beta plus with acute chest syndrome
A combination blood disorder with sickle-cell and thalassemia beta-plus that causes acute chest syndrome, a serious lung complication with chest pain and breathing difficulty.
Buddy Insight
Acute chest syndrome in sickle-cell thalassemia beta plus is the same life-threatening pulmonary complication seen in other sickle cell genotypes, though it may occur less frequently in beta-plus patients due to the milder overall disease phenotype.
CMS-HCC V28
MappedHCC 108
RAF 0.146
CMS-HCC V24
MappedHCC 46
RAF 1.372
ACA/HHS
MappedHCC 71
Varies by metal level
ESRD/PACE
MappedHCC 46
RAF 0.223
RXHCC
N/A—
Not mapped
Code Book Path
Inclusion Terms
Official- HbS-beta plus with acute chest syndrome
- Sickle-cell beta plus with acute chest syndrome
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for D57.451 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for D57.451 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for D57.451 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for D57.451 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for D57.451 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for D57.451 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →
Is D57.451 an HCC code?
Yes. D57.451 (Sickle-cell thalassemia beta plus with acute chest syndrome) maps to Sickle Cell Disorders, Except Sickle Cell Anemia (Hb-SS) and Thalassemia Beta Zero; Beta Thalassemia Major under the CMS-HCC V28 risk adjustment model (and Severe Hematological Disorders under V24), with a community non-dual aged RAF of 0.146. It is billable for payment year 2026.
Coder answer: D57.451 is billable and maps to V28 HCC 108, Sickle Cell Disorders, Except Sickle Cell Anemia (Hb-SS) and Thalassemia Beta Zero; Beta Thalassemia Major. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.
- Code
- D57.451
- Description
- Sickle-cell thalassemia beta plus with acute chest syndrome
- HCC (V28)
- HCC 108 — Sickle Cell Disorders, Except Sickle Cell Anemia (Hb-SS) and Thalassemia Beta Zero; Beta Thalassemia Major
- RAF
- 0.146
- Billable
- Yes
- Payment year
- 2026
HCC Category Mapping
Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.
Work D57.451 in the Code Book — tabular path, V28 RAF, and MEAT checklist →
MEAT Criteria for D57.451
For D57.451 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 D57.451 during that encounter, not just copy-forwarded from a problem list.
Coder workflow notes
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What This Code Means
D57.451 is the ICD-10-CM diagnosis code for sickle-cell thalassemia beta plus with acute chest syndrome. A combination blood disorder with sickle-cell and thalassemia beta-plus that causes acute chest syndrome, a serious lung complication with chest pain and breathing difficulty. D57.451 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, D57.451 maps to Sickle Cell Disorders, Except Sickle Cell Anemia (Hb-SS) and Thalassemia Beta Zero; Beta Thalassemia Major (HCC 108) with a community, non-dual, aged base RAF weight of 0.146. Under the older CMS-HCC V24 model, D57.451 maps to Severe Hematological Disorders (HCC 46) with a community, non-dual, aged base RAF weight of 1.372. 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; document respiratory symptoms, fever, chest pain, and imaging findings (chest X-ray or CT). Because D57.451 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 D57.451 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; document respiratory symptoms, fever, chest pain, and imaging findings (chest X-ray or CT)
- •Distinguish from D57.431 by confirming beta-plus (not beta-zero) thalassemia is documented
Clinical Significance
Acute chest syndrome in sickle-cell thalassemia beta plus is the same life-threatening pulmonary complication seen in other sickle cell genotypes, though it may occur less frequently in beta-plus patients due to the milder overall disease phenotype. Despite the generally milder course, acute chest syndrome can still be severe and potentially fatal, requiring the same aggressive management with exchange transfusion, antibiotics, and respiratory support.
Documentation Requirements
- ✓Documentation must confirm the sickle-cell thalassemia beta plus genotype and the explicit diagnosis of acute chest syndrome with new pulmonary infiltrate and respiratory symptoms (chest pain, dyspnea, cough, fever, hypoxia).
- ✓Record oxygen saturation, imaging results, treatment protocol, and clinical course.
- ✓The provider must document 'acute chest syndrome' as the diagnosis.