2026 ICD-10-CM Diagnosis Code E02Subclinical iodine-deficiency hypothyroidism

ICD-10-CM Codes›E00–E89›E00-E07›E02

ICD-10-CM E02
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E02 is a billable ICD-10-CM diagnosis code for subclinical iodine-deficiency hypothyroidism. 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. Coders also document this condition as iodine hypothyroidism. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Thyroid disorders.

Code Identity

ICD-10-CM Code
E02
Billable Status
Yes — Valid for Submission
Code Describes
Subclinical iodine-deficiency hypothyroidism
Chapter
E00-E07
Disorders of thyroid gland

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE00-E07Disorders of thyroid gland
CategoryE02Subclinical iodine-deficiency hypothyroidism
This CodeE02Subclinical iodine-deficiency hypothyroidism

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Iodine hypothyroidism
  • Myxedema coma
  • Myxedema coma due to subclinical hypothyroidism
  • Subclinical disease AND/OR syndrome
  • Subclinical hypothyroidism
  • Subclinical iodine deficiency hypothyroidism

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.

    • Hypothyroidism(acquired)
      • due to
        • iodine-deficiency, acquired
          • subclinical
    • Hypothyroidism(acquired)
      • iodine-deficiency (acquired)
        • subclinical
    • Hypothyroidism(acquired)
      • subclinical, iodine-deficiency related

Clinical ClassificationClinical

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

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

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 E02 to ICD-9-CMHistory

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

ICD-9-CM
244.8 Acquired hypothyroid NEC
Approximate The match is approximate rather than exact.

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 E02Overview

Is E02 (Subclinical iodine-deficiency hypothyroidism) a billable code?

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

What MS-DRG does E02 group to?

When subclinical iodine-deficiency hypothyroidism 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 E02?

Under the General Equivalence Mappings, subclinical iodine-deficiency hypothyroidism converts to ICD-9-CM 244.8 (acquired hypothyroid NEC). The mapping is approximate, so confirm the match fits the documentation.

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.