2026 ICD-10-CM Diagnosis Code E03.9Hypothyroidism, unspecified

ICD-10-CM Codes›E00–E89›E00-E07›E03

ICD-10-CM E03.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E03.9 is a billable ICD-10-CM diagnosis code for hypothyroidism, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 643 through 645. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Thyroid disorders.

Code Identity

ICD-10-CM Code
E03.9
Billable Status
Yes — Valid for Submission
Code Describes
Hypothyroidism, unspecified
Short Description
Hypothyroidism, unspecified
Same as the full description in the CMS dataset.
Parent Code
E03
Other hypothyroidism

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE00-E07Disorders of thyroid gland
CategoryE03Other hypothyroidism
This CodeE03.9Hypothyroidism, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acquired central hypothyroidism
  • Acquired hypothyroidism
  • Adult myxedema
  • Central hypothyroidism
  • Cerebral degeneration due to hypothyroidism
  • Chronic pericarditis
  • Dementia due to acquired hypothyroidism
  • Endocrine myopathy
  • Endogenous obesity
  • Hoffman syndrome
  • Hyperprolactinemia due to hypothyroidism
  • Hypertrichosis in hypothyroidism
  • Hypothyroid myopathy
  • Hypothyroid obesity
  • Hypothyroidism
  • Hypothyroidism due to infiltrative disease
  • Hypothyroidism due to sarcoidosis
  • Hypothyroidism due to thyroiditis
  • Hypothyroidism in childbirth
  • Hypothyroidism in pregnancy
  • Juvenile myxedema
  • Myasthenic syndrome due to another disorder
  • Myasthenic syndrome due to hypothyroidism
  • Myxedema
  • Myxedema cerebellar degeneration
  • Myxedema neuropathy
  • Obesity by contributing factors
  • Obesity of endocrine origin
  • Pericarditis secondary to myxedema
  • Premature puberty due to hypothyroidism
  • Primary hypothyroidism
  • Pseudohypertrophy of muscle
  • Secondary cerebellar degeneration
  • Severe hypothyroidism
  • Subclinical disease AND/OR syndrome
  • Subclinical hypothyroidism
  • Subclinical hypothyroidism in pregnancy
  • Thyroid disease in pregnancy
  • Transient decreased production of T>4<

Tabular List NotesGuidance

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

Inclusion Terms

  • Myxedema NOS

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)
      • due to (in) (with)
        • myxedema
    • Arthritis, arthritic(acute) (chronic) (nonpyogenic) (subacute)
      • in (due to)
        • hypothyroidism NEC
    • Arthropathy
      • in (due to)
        • hypothyroidism
    • Ataxia, ataxy, ataxic
      • cerebellar (hereditary)
        • in
          • myxedema
    • Atrophy, atrophic(of)
      • systemic affecting central nervous system
        • in
          • myxedema
    • Cataract(cortical) (immature) (incipient)
      • myxedema
    • Degeneration, degenerative
      • brain (cortical) (progressive)
        • in
          • myxedema
    • Dementia(degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety)
      • in (due to)
        • hypothyroidism, acquired
    • Dementia(degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety)
      • in (due to)
        • hypothyroidism, acquired
          • with behavioral disturbance
    • Hoffmann's syndrome
    • Hypothyroidism(acquired)
    • Insufficiency, insufficient
      • thyroid (gland) (acquired)
    • Myopathy
      • in (due to)
        • hypothyroidism
    • Myopathy
      • in (due to)
        • myxedema
    • Myxedema(adult) (idiocy) (infantile) (juvenile)

Clinical ClassificationClinical

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

CCSR END001
Thyroid disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Congenital Hypothyroidism

    a condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. endemic cretinism is the result of iodine deficiency. clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.

  • Hypothyroidism

    a syndrome that results from abnormally low secretion of thyroid hormones from the thyroid gland, leading to a decrease in basal metabolic rate. in its most severe form, there is accumulation of mucopolysaccharides in the skin and edema, known as myxedema. it may be primary or secondary due to other pituitary disease, or hypothalamic dysfunction.

  • Myxedema

    a condition characterized by a dry, waxy type of swelling (edema) with abnormal deposits of mucopolysaccharides in the skin and other tissues. it is caused by a deficiency of thyroid hormones. the skin becomes puffy around the eyes and on the cheeks. the face is dull and expressionless with thickened nose and lips.

  • Scleromyxedema

    a connective tissue disorder characterized by widespread thickening of skin with a cobblestone-like appearance. it is caused by proliferation of fibroblasts and deposition of mucin in the dermis in the absence of thyroid disease. most scleromyxedema cases are associated with a monoclonal gammopathy, immunoglobulin igg-lambda.

  • Graves Disease with Pretibial Myxedema and Thyrotoxic Crisis|Graves' disease with pretibial myxedema AND with thyrotoxic crisis

    graves disease associated with thyrotoxic crisis and cutaneous non-pitting edema and plaque formation.

  • Acquired Hypothyroidism

    hypothyroidism, the cause of which is not present at birth.

  • Congenital Iodine Deficiency Syndrome, Myxedematous Type|Congenital iodine-deficiency syndrome, myxedematous type

    congenital iodine deficiency syndrome associated with milder mental retardation, short stature, goiter, and hypothyroidism. it results from iodine deficiency and hypothyroidism in the fetus during late pregnancy or in the neonatal period.

  • Myxedema

    a condition characterized by severe hypothyroidism that is caused by autoimmune thyroid gland disorders, surgical reduction of thyroid tissue, radiation exposure, and viral infections. signs and symptoms include generalized fatigue, lethargy, increased body weight, pale, edematous and thickened skin, low blood pressure, constipation and cold intolerance.

  • Myxedema Coma|Myxedema coma

    a life-threatening condition characterized by altered mental status and defective thermoregulation. it is seen in individuals with severe, decompensated hypothyroidism.

  • Scleromyxedema

    a rare chronic and progressive skin disorder characterized by mucin deposition in the skin, resulting in the thickening and hardening of the skin, predominantly in the face, fingers, and extremities.

  • Systemic Atrophy Primarily Affecting the Central Nervous System in Myxedema|Systemic atrophy primarily affecting the central nervous system in myxedema

    evidence of systemic atrophy primarily affecting the central nervous system in myxedema.

  • Iatrogenic Primary Hypothyroidism

    primary hypothyroidism due to medical or surgical treatment.

  • Primary Hypothyroidism

    abnormally low levels of thyroid hormones due to a disorder originating within the thyroid gland.

  • Transient Primary Hypothyroidism

    primary hypothyroidism that resolves spontaneously.

  • Acquired Central Hypothyroidism

    central hypothyroidism, the cause of which is not present at birth.

Patient EducationClinical

Hypothyroidism

Hypothyroidism, or underactive thyroid, happens when your thyroid gland doesn't make enough thyroid hormones to meet your body's needs.

The full article covers:

  • What is hypothyroidism?
  • What causes hypothyroidism?
  • Who is at risk for hypothyroidism?
  • What are the symptoms of hypothyroidism?
  • What other problems can hypothyroidism cause?
  • How is hypothyroidism diagnosed?
  • What are the treatments for hypothyroidism?

Read the full article at MedlinePlus

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

Convert E03.9 to ICD-9-CMHistory

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

ICD-9-CM
244.9 Hypothyroidism NOS
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 E03.9Overview

Is E03.9 (Other hypothyroidism) a billable code?

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

What MS-DRG does E03.9 group to?

When hypothyroidism, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 643, 644, 645, with relative weights from 0.7683 to 1.6461 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of E03.9?

Under the General Equivalence Mappings, hypothyroidism, unspecified converts to ICD-9-CM 244.9 (hypothyroidism NOS). 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.