2026 ICD-10-CM Diagnosis Code D55.21Anemia due to pyruvate kinase deficiency

ICD-10-CM Codes›D50–D89›D55-D59›D55

ICD-10-CM D55.21
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

D55.21 is a billable ICD-10-CM diagnosis code for anemia due to pyruvate kinase deficiency. 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. Coders also document this condition as HNSHA due to pyruvate kinase deficiency. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Hemolytic anemia.

Code Identity

ICD-10-CM Code
D55.21
Billable Status
Yes — Valid for Submission
Code Describes
Anemia due to pyruvate kinase deficiency
Short Description
Anemia due to pyruvate kinase deficiency
Same as the full description in the CMS dataset.
Parent Code
D55.2
Anemia due to disorders of glycolytic enzymes

Code Classification

ChapterD50–D89Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
SectionD55-D59Hemolytic anemias
CategoryD55Anemia due to enzyme disorders
This CodeD55.21Anemia due to pyruvate kinase deficiency

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • HNSHA due to pyruvate kinase deficiency

Tabular List NotesGuidance

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

Inclusion Terms

  • PK deficiency anemia
  • Pyruvate kinase deficiency anemia

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.

    • Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
      • deficiency
        • PK
    • Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
      • deficiency
        • pyruvate kinase
    • Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
      • hemolytic
        • nonspherocytic
          • congenital or hereditary NEC
            • pyruvate kinase deficiency
    • Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
      • pyruvate kinase deficiency

Clinical ClassificationClinical

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

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

Patient EducationClinical

Anemia

If you have anemia, your blood does not carry enough oxygen to the rest of your body. The most common cause of anemia is not having enough iron. Your body needs iron to make hemoglobin. Hemoglobin is an iron-rich protein that gives the red color to blood. It carries oxygen from the lungs to the rest of the body.

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement D55.21 replaces the following previously assigned code(s):

  • D55.2 - Anemia due to disorders of glycolytic enzymes
FY 2022AddedAdded to the ICD-10-CM code setEffective October 1, 2021.
FY 2023–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About D55.21Overview

Is D55.21 (Anemia due to disorders of glycolytic enzymes) a billable code?

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

What MS-DRG does D55.21 group to?

When anemia due to pyruvate kinase deficiency 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.

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.