2026 ICD-10-CM Diagnosis Code D56.0Alpha thalassemia

ICD-10-CM Codes›D50–D89›D55-D59›D56

ICD-10-CM D56.0
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D56.0 is a billable ICD-10-CM diagnosis code for alpha thalassemia. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 811 through 812. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hemolytic anemia.

Code Identity

ICD-10-CM Code
D56.0
Billable Status
Yes — Valid for Submission
Code Describes
Alpha thalassemia
Short Description
Alpha thalassemia
Same as the full description in the CMS dataset.
Parent Code
D56
Thalassemia

Code Classification

ChapterD50–D89Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
SectionD55-D59Hemolytic anemias
CategoryD56Thalassemia
This CodeD56.0Alpha thalassemia

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acquired hemoglobin H disease
  • Alpha plus thalassemia
  • Alpha plus thalassemia deletion type
  • Alpha plus thalassemia non deletion type
  • Alpha thalassemia
  • Alpha thalassemia X-linked intellectual disability syndrome
  • Alpha zero thalassemia
  • Alpha-thalassemia intellectual disability syndrome linked to chromosome 16
  • Deletion of part of short arm of chromosome 16
  • Fetal anemia
  • Fetal hereditary disease
  • Hemoglobin Bart's hydrops syndrome
  • Hemoglobin H constant spring thalassemia
  • Hemoglobin H disease
  • Hemoglobin Paksé disease
  • Hemoglobin Seal Rock disease
  • Homozygous alpha thalassemia
  • Hydrops fetalis
  • Sickle cell anemia with coexistent alpha-thalassemia
  • Sickle cell-hemoglobin SS disease
  • Sickle cell-thalassemia disease

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Alpha thalassemia major
  • Hemoglobin H Constant Spring
  • Hemoglobin H disease
  • Hydrops fetalis due to alpha thalassemia
  • Severe alpha thalassemia
  • Triple gene defect alpha thalassemia

Use Additional Code

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

Type 1 Excludes

  • 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

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Disease, diseased
      • hemoglobin or Hb
        • Bart's
    • Disease, diseased
      • hemoglobin or Hb
        • H (Hb-H) (thalassemia)
    • Disease, diseased
      • hemoglobin or Hb
        • H (Hb-H) (thalassemia)
          • Constant Spring
    • Hb(abnormal)
      • Bart's disease
    • Hemoglobin
      • H Constant Spring
    • Hydrops
      • fetalis
        • due to
          • alpha thalassemia
    • Hydrops
      • newborn (idiopathic)
        • due to
          • alpha thalassemia
    • Thalassemia(anemia) (disease)
      • alpha (major) (severe) (triple gene defect)

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR BLD002
Hemolytic anemia
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Hydrops Fetalis

    abnormal accumulation of serous fluid in two or more fetal compartments, such as skin; pleura; pericardium; placenta; peritoneum; amniotic fluid. general fetal edema may be of non-immunologic origin, or of immunologic origin as in the case of erythroblastosis fetalis.

  • Transfusion Dependent Alpha Thalassemia|Transfusion-dependent Alpha Thalassemia

    alpha thalassemia that results in severe anemia and requires regular blood transfusions for patient survival.

  • Alpha Thalassemia

    a genetic hematologic disorder characterized by partial or complete absence of the alpha globin chains of the heme molecule.

  • Alpha Thalassemia Silent Carrier

    a condition in which a person has reduced protein production from one of the four alpha-globin alleles.

  • Alpha Thalassemia Trait

    a condition in which a person has reduced protein production from two of the four alpha-globin alleles.

  • Alpha Thalassemia X-Linked Mental Retardation Syndrome|ATRX|Alpha Thalassemia/Mental Retardation Syndrome X-Linked

    a rare, x-linked recessive inherited syndrome caused by mutations in the atrx gene. it is characterized by intellectual disability, developmental delays, hypotonia, widely spaced eyes, small nose, low-set ears, tented upper lip, skeletal abnormalities, and a mild form of alpha thalassemia.

  • ATRX Gene Mutation Negative|ATRX Mutation Negative|ATRX Wild-Type|ATRX Wildtype|ATRX wt|ATRX, Chromatin Remodeler Gene Mutation Negative|Alpha Thalassemia/Mental Retardation Syndrome X-Linked Gene Mutation Negative|Negative|No|RAD54 Gene Mutation Negative|RAD54 Homolog Gene Mutation|RAD54L Gene Mutation Negative|XH2 Gene Mutation Negative|XNP Gene Mutation Negative|ZNF-HX Gene Mutation Negative

    a genetic finding indicating that atrx gene mutations have not been detected in a sample.

  • ATRX Gene Mutation|ATRX|ATRX, Chromatin Remodeler Gene Mutation|Alpha Thalassemia/Mental Retardation Syndrome X-Linked Gene Mutation|Positive|RAD54 Gene Mutation|RAD54 Homolog Gene Mutation|RAD54L Gene Mutation|XH2 Gene Mutation|XNP Gene Mutation|Yes|ZNF-HX Gene Mutation

    a change in the nucleotide sequence of the atrx gene.

  • ATRX Mutation Analysis|ATRX Gene Mutation Analysis|ATRX Mutation Status|ATRX, Chromatin Remodeler Mutation Analysis|Alpha Thalassemia/Mental Retardation Syndrome X-Linked Mutation Analysis|RAD54 Homolog Mutation Analysis|RAD54 Mutation Analysis|RAD54L Mutation Analysis|XH2 Mutation Analysis|XNP Mutation Analysis|ZNF-HX Mutation Analysis

    a procedure used to detect and identify mutations in the alk gene.

  • ATRX Mutation Status by Sequencing|ATRX Sequencing|Alpha Thalassemia/Mental Retardation Syndrome X-Linked Mutation Analysis by Sequencing|RAD54 Homolog Mutation Analysis by Sequencing|RAD54 Mutation Analysis by Sequencing|RAD54L Mutation Analysis by Sequencing|XH2 Mutation Analysis by Sequencing|XNP Mutation Analysis by Sequencing|ZNF-HX Mutation Analysis by Sequencing

    an indication that the presence or absence of atrx gene mutations was determined using sequencing techniques.

  • ATRX wt Allele|ATR-X Gene|ATR2|ATRX, Chromatin Remodeler wt Allele|Alpha Thalassemia/Mental Retardation Syndrome X-Linked (RAD54 (S. cerevisiae) Homolog) Gene|Alpha Thalassemia/Mental Retardation Syndrome X-Linked (RAD54 Homolog, S. cerevisiae) Gene|Alpha Thalassemia/Mental Retardation Syndrome X-Linked Gene|Helicase 2, X-Linked Gene|Juberg-Marsidi Syndrome Gene|MGC2094|MRXHF1|Mental Retardation, X-Linked 52 Gene|RAD54|RAD54 Homolog (S. cerevisiae) Gene|RAD54L|SFM1|SHS|X-Linked Nuclear Protein Gene|XH2|XNP|ZNF-HX

    human atrx wild-type allele is located within xq13.1-q21.1 and is approximately 281 kb in length. this allele, which encodes transcriptional regulator atrx protein, is involved in the modulation of both transcription and chromatin structure. mutations in the gene are associated with x-linked alpha-thalassemia/mental retardation syndrome, mental retardation syndromic x-linked with hypotonic facies syndrome type 1, and alpha-thalassemia myelodysplasia syndrome.

  • Deleterious ATRX Gene Mutation|Deleterious ATRX Mutation|Deleterious ATRX, Chromatin Remodeler Gene Mutation|Deleterious Alpha Thalassemia/Mental Retardation Syndrome X-Linked Gene Mutation|Deleterious RAD54 Gene Mutation|Deleterious RAD54 Homolog Gene Mutation|Deleterious RAD54L Gene Mutation|Deleterious XH2 Gene Mutation|Deleterious XNP Gene Mutation|Deleterious ZNF-HX Gene Mutation

    a change in the nucleotide sequence of the atrx gene that is associated with increased risk of disease.

  • Inactivating ATRX Gene Mutation|ATRX Gene Inactivation|ATRX Loss of Function Gene Mutation|ATRX Loss of Function Mutation|Inactivating ATRX Mutation|Inactivating ATRX, Chromatin Remodeler Gene Mutation|Inactivating Alpha Thalassemia/Mental Retardation Syndrome X-Linked Gene Mutation|Inactivating RAD54 Gene Mutation|Inactivating RAD54 Homolog Gene Mutation|Inactivating RAD54L Gene Mutation|Inactivating XH2 Gene Mutation|Inactivating XNP Gene Mutation|Inactivating ZNF-HX Gene Mutation|Loss of Function ATRX Gene Mutation|Loss of Function ATRX Mutation

    a change in the nucleotide sequence of the atrx gene that either inhibits expression or results in the translation of an inactive transcriptional regulator atrx protein.

  • Rapid Screening Method for Alpha Thalassemia

    screening techniques for alpha thalassemia that use melting curve analysis of pcr products generated from the alpha globin alleles.

  • Hydrops Fetalis

    a condition characterized by fluid accumulation in two or more anatomic compartments in the fetus.

  • Immune Hydrops Fetalis

    fluid accumulation in multiple fetal anatomic cavities attributable to a maternal immune response against fetal blood cell antigens.

  • Non-Immune Hydrops Fetalis

    fluid accumulation in multiple fetal anatomic cavities that is of non-immune origin.

  • Hemoglobin H Disease

    a form of alpha thalassemia that results from reduced protein production from three of the four alpha-globin genes. clinically it is characterized by chronic hemolytic anemia.

Patient EducationClinical

Thalassemia

Thalassemias are inherited blood disorders. If you have one, your body makes fewer healthy red blood cells and less hemoglobin. Hemoglobin is a protein that carries oxygen to the body. That leads to anemia. Thalassemias occur most often among people of Italian, Greek, Middle Eastern, Southern Asian, and African descent.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert D56.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
282.43 Alpha thalassemia
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About D56.0Overview

Is D56.0 (Thalassemia) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report alpha thalassemia on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does D56.0 group to?

When alpha thalassemia is the principal diagnosis on an inpatient stay, it groups to MS-DRG 811, 812, with relative weights from 0.9182 to 1.4043 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of D56.0?

Under the General Equivalence Mappings, alpha thalassemia converts to ICD-9-CM 282.43 (alpha thalassemia). The mapping is a direct match.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.