2026 ICD-10-CM Diagnosis Code E03.4Atrophy of thyroid (acquired)
ICD-10-CM Codes›E00–E89›E00-E07›E03
- Billable — Valid for Submission
- Chronic Condition
E03.4 is a billable ICD-10-CM diagnosis code for atrophy of thyroid (acquired). It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 11 through 13, 643 through 645. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Thyroid disorders.
E03.4 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 44 for payment year 2026.
Code Identity
Code Classification
Medicare Risk Adjustment (HCC)Billing
E03.4 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.
Source: CMS Payment Year 2026 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Atrophic Hashimoto thyroiditis
- Atrophy of thyroid - acquired
- Autoimmune thyroiditis
- Chronic thyroiditis
- Hashimoto thyroiditis
- Idiopathic atrophic hypothyroidism
- Thyroid atrophy
- Thyroid degeneration
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 1 Excludes
- congenital atrophy of thyroid E03.1
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
strumipriva E03.4
Gull's disease E03.4
Strumipriva cachexia E03.4
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
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.
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 E03.4 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About E03.4Overview
What is the ICD-10 code for atrophy of thyroid (acquired)?
The ICD-10-CM code for atrophy of thyroid (acquired) is E03.4 (sometimes written as E034). It is billable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
Is E03.4 (Other hypothyroidism) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report atrophy of thyroid (acquired) on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What MS-DRG does E03.4 group to?
When atrophy of thyroid (acquired) is the principal diagnosis on an inpatient stay, it groups to MS-DRG 11, 12, 13, 643, 644, 645, with relative weights from 0.7683 to 5.4541 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of E03.4?
Under the General Equivalence Mappings, atrophy of thyroid (acquired) converts to ICD-9-CM 246.8 (disorders of thyroid NEC). The mapping is approximate, so confirm the match fits the documentation.
Does E03.4 risk-adjust for Medicare Advantage payment?
Not for Medicare Advantage: E03.4 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 44 (Thyroid Disorders).
