What is ICD-10 code D56.0?

D56.0 is the ICD-10-CM diagnosis code for Alpha thalassemia. Alpha thalassemia is an inherited blood disorder where the body doesn't make enough alpha-globin protein, a component of hemoglobin that carries oxygen in red blood cells. This results in anemia, fatigue, and potentially serious complications if severe. D56.0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. D56.0 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. D56.0 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. D56.0 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does D56.0 map to under V28?

D56.0 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

What RAF reference is published for D56.0?

D56.0 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

What is the V28 vs V24 difference for D56.0?

D56.0 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

What documentation supports D56.0?

Verify the specific type of alpha thalassemia (such as alpha thalassemia trait, HbH disease, or hydrops fetalis) in the clinical documentation, as these may require additional specificity codes Check for associated complications like splenomegaly, bone deformities, or transfusion dependency that should be coded separately to capture the full clinical picture D56.0 is not a CMS-HCC V28 payment code in the verified current source, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

2026 ICD-10-CM D56.0: Alpha thalassemia

D56.0 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · free HCC coding tools

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupD56.0Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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)

D56.0

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Alpha thalassemia

Alpha thalassemia is an inherited blood disorder where the body doesn't make enough alpha-globin protein, a component of hemoglobin that carries oxygen in red blood cells. This results in anemia, fatigue, and potentially serious complications if severe.

Buddy Insight

Alpha thalassemia encompasses a spectrum of inherited hemoglobin disorders caused by deletion or mutation of one to four alpha-globin genes.

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

N/A

—

Not risk-adjusted for this model/period.

Not mapped

ESRD/PACE

Mapped

HCC 48

Coagulation Defects and Other...

Code-level coefficient reference

RXHCC

N/A

—

Not risk-adjusted for this model/period.

Not mapped

Code Book Path

Official

D56Thalassemia

D56.0Alpha thalassemia

Inclusion Terms

Official

Alpha thalassemia major
Hemoglobin H Constant Spring
Hemoglobin H disease
Hydrops fetalis due to alpha thalassemia
Severe alpha thalassemia

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for D56.0 in this effective period.

Related Child Codes

Official

D56.1Beta thalassemia

D56.2Delta-beta thalassemia

D56.3Thalassemia minor

D56.4Hereditary persistence of fetal hemoglobin [HPFH]

D56.5Hemoglobin E-beta thalassemia

Includes

Official

ICD-10-CM does not list Includes notes for D56.0 in this effective period.

Excludes 1

Official

alpha thalassemia trait or minor (D56.3)
asymptomatic alpha thalassemia (D56.3)
hydrops fetalis due to isoimmunization (P56.0)
hydrops fetalis not due to immune hemolysis (P83.2)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for D56.0 in this effective period.

Use Additional

Official

code, if applicable, for hydrops fetalis due to alpha thalassemia (P56.99)

Code Also

Official

ICD-10-CM does not list Code Also instructions for D56.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation must specify the type and severity of alpha thalassemia (silent carrier, trait, Hemoglobin H disease, or hydrops fetalis) with supporting genetic testing or hemoglobin electrophoresis results.

Record baseline hemoglobin and mean corpuscular volume, transfusion requirements, iron studies to differentiate from iron deficiency, and any complications such as splenomegaly or bone deformities.

Genetic counseling status should be noted.

MEAT Support

HCC Buddy guidance

Record baseline hemoglobin and mean corpuscular volume, transfusion requirements, iron studies to differentiate from iron deficiency, and any complications such as splenomegaly or bone deformities.

Genetic counseling status should be noted.

Audit Caution

HCC Buddy guidance

This code has no V28 HCC mapping and will lose risk adjustment value in the model transition. Alpha thalassemia trait (two-gene deletion) is often an incidental finding and may not require active management, but should still be documented as a chronic condition. Do not confuse with iron deficiency anemia -

iron studies will be normal or elevated in thalassemia. Ensure the provider documents alpha thalassemia specifically, not just 'thalassemia trait.'

Common Mistakes

HCC Buddy guidance

D56.0 vs. D56.1 (Beta thalassemia) -

different globin chain affected with distinct genetic basis and clinical features. D56.0 vs. D50.9 (Iron deficiency anemia, unspecified) -

alpha thalassemia trait is commonly misdiagnosed as iron deficiency due to microcytosis. D56.0 vs. D56.3 (Thalassemia minor) -

D56.3 is for thalassemia minor not otherwise specified, while D56.0 is specifically alpha thalassemia.

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 D56.0 an HCC code?

D56.0 is not in the CMS-HCC V28 or V24 community payment model. D56.0 has a separate mapping under the CMS-HCC ESRD model (HCC 48 (Coagulation Defects and Other Specified Hematological Disorders)); the applicable result needs member context.

Code: D56.0
Description: Alpha thalassemia
HCC (V28): No CMS-HCC V28 mapping
RAF reference coefficient: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

ESRDHCC 48, Coagulation Defects and Other Specified Hematological Disorders

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work D56.0 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for D56.0

For D56.0 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 D56.0 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

D56.0 is the ICD-10-CM diagnosis code for alpha thalassemia. Alpha thalassemia is an inherited blood disorder where the body doesn't make enough alpha-globin protein, a component of hemoglobin that carries oxygen in red blood cells. This results in anemia, fatigue, and potentially serious complications if severe. D56.0 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).

D56.0 has no mapping under the CMS-HCC V28 or V24 community payment models. D56.0 has a separate mapping under the CMS-HCC ESRD model (HCC 48 (Coagulation Defects and Other Specified Hematological Disorders)); the applicable result needs member context. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.

Verify the specific type of alpha thalassemia (such as alpha thalassemia trait, HbH disease, or hydrops fetalis) in the clinical documentation, as these may require additional specificity codes.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for D56.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Verify the specific type of alpha thalassemia (such as alpha thalassemia trait, HbH disease, or hydrops fetalis) in the clinical documentation, as these may require additional specificity codes
•Check for associated complications like splenomegaly, bone deformities, or transfusion dependency that should be coded separately to capture the full clinical picture

Clinical Significance

Alpha thalassemia encompasses a spectrum of inherited hemoglobin disorders caused by deletion or mutation of one to four alpha-globin genes. Clinical severity ranges from the silent carrier state (one gene affected) and alpha thalassemia trait (two genes) to Hemoglobin H disease (three genes) and the fatal hydrops fetalis (four genes). This is particularly prevalent in Southeast Asian, African, and Mediterranean populations, and proper classification impacts genetic counseling and clinical management.

Documentation Requirements

✓Documentation must specify the type and severity of alpha thalassemia (silent carrier, trait, Hemoglobin H disease, or hydrops fetalis) with supporting genetic testing or hemoglobin electrophoresis results.
✓Record baseline hemoglobin and mean corpuscular volume, transfusion requirements, iron studies to differentiate from iron deficiency, and any complications such as splenomegaly or bone deformities.
✓Genetic counseling status should be noted.

Excludes 1, Do NOT code together

alpha thalassemia trait or minor (D56.3)
asymptomatic alpha thalassemia (D56.3)
hydrops fetalis due to isoimmunization (P56.0)
hydrops fetalis not due to immune hemolysis (P83.2)

Use Additional Code

code, if applicable, for hydrops fetalis due to alpha thalassemia (P56.99)

Commonly Confused Codes

•D56.0 vs. D56.1 (Beta thalassemia) -
•different globin chain affected with distinct genetic basis and clinical features. D56.0 vs. D50.9 (Iron deficiency anemia, unspecified) -
•alpha thalassemia trait is commonly misdiagnosed as iron deficiency due to microcytosis. D56.0 vs. D56.3 (Thalassemia minor) -
•D56.3 is for thalassemia minor not otherwise specified, while D56.0 is specifically alpha thalassemia.