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ICD-10 Code E03.9: Hypothyroidism, unspecified

E03.9 is a billable ICD-10 diagnosis code used to classify Hypothyroidism, unspecified in medical records and claims. You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records. ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Endocrine, nutritional and metabolic diseases (E00-E89).

What is this code?

ICD-10 codes are diagnosis classification codes used in healthcare records, reporting, coding workflows, and billing support. This code sits within the broader ICD-10 area for Endocrine, nutritional and metabolic diseases (E00-E89).

šŸ“‹Clinical overview

This ICD-10 code is commonly used when documentation describes hypothyroidism or another closely related thyroid-hormone deficiency pattern in the E03 family. The most accurate code depends on whether the record identifies congenital, drug-induced, postinfectious, atrophic, myxedema-coma, other specified, or unspecified hypothyroidism.

When is it used?

  • May be used when a clinician documents hypothyroidism, unspecified in a patient's medical record.
  • May appear in hospital records, claims, referrals, and clinical documentation.
  • This code can be used as a clinically usable diagnosis entry in standardized coding workflows.

What it does not mean

  • A code alone does not explain severity, treatment plan, or outcome.
  • A medical code should not be treated as a substitute for a doctor's diagnosis or advice.

šŸ©ŗClinical context

When commonly used
  • Primary-care, endocrinology, inpatient, and utilization-review workflows where thyroid-hormone deficiency, thyroid replacement follow-up, or severe decompensated hypothyroid illness is part of the assessment.
  • Coding workflows where the chart identifies congenital status, medication or exogenous cause, infection-related onset, myxedema-coma severity, or another specific hypothyroid pattern that changes final code specificity.
Common workup
  • Common related testing on this page includes TSH, Free T4, Anti-thyroid peroxidase antibody.
Common management context
  • Evaluation often includes TSH and free-thyroxine review, symptom assessment for fatigue, cold intolerance, constipation, weight change, or altered mental status, and thyroid-replacement or endocrine follow-up planning.
  • Documentation usually becomes more specific when the chart identifies congenital versus acquired disease, drug-related or postinfectious cause, thyroid atrophy, myxedema-coma severity, or another specified hypothyroid pattern.
  • Specialist context already linked on this page includes Endocrinologist, General Physician.

šŸ”Key distinctions

Important notes
  • This ICD-10 family captures hypothyroidism and closely related thyroid-hormone deficiency states rather than thyroiditis, hyperthyroidism, or non-thyroid endocrine disorders.
  • Cause and severity detail, such as congenital pattern, exogenous cause, postinfectious state, thyroid atrophy, myxedema coma, other specified form, or unspecified disease, drives final code specificity inside this family.
  • This title preserves unspecified hypothyroidism detail; if the chart identifies the cause, congenital status, or another specific pattern more clearly, a more specific code may be used.
  • Documentation that describes hypothyroidism is coded differently from thyroiditis, thyrotoxicosis, hyperparathyroidism, or other endocrine disorders without documented thyroid-hormone deficiency.
Related codes to consider
E03.0Congenital hypothyroidism with diffuse goiter
Related hypothyroidism ICD-10 code; documentation often becomes more specific when the chart identifies congenital versus acquired disease, drug-induced or postinfectious cause, myxedema coma, or another specified versus unspecified hypothyroid pattern.
E03.1Congenital hypothyroidism without goiter
Related hypothyroidism ICD-10 code; documentation often becomes more specific when the chart identifies congenital versus acquired disease, drug-induced or postinfectious cause, myxedema coma, or another specified versus unspecified hypothyroid pattern.
E03.2Hypothyroidism due to medicaments and other exogenous substances
Related hypothyroidism ICD-10 code; documentation often becomes more specific when the chart identifies congenital versus acquired disease, drug-induced or postinfectious cause, myxedema coma, or another specified versus unspecified hypothyroid pattern.
E03.3Postinfectious hypothyroidism
Related hypothyroidism ICD-10 code; documentation often becomes more specific when the chart identifies congenital versus acquired disease, drug-induced or postinfectious cause, myxedema coma, or another specified versus unspecified hypothyroid pattern.

Code hierarchy

chapter
4Endocrine, nutritional and metabolic diseases (E00-E89)
block
E00-E07Disorders of thyroid gland
category
E03Other hypothyroidism
currentE03

Official coding notes

Inclusion terms
  • Myxedema NOS

Where you may see this code

You may see this code in hospital records, discharge summaries, insurance claims, encounter documentation, referrals, or other healthcare billing and coding records.

Related specialists

EndocrinologistGeneral Physician

Related tests

TSH
Commonly reviewed in hypothyroidism evaluation.
Free T4
Often reviewed alongside TSH in thyroid assessment.
Anti-thyroid peroxidase antibody
May be relevant when autoimmune thyroid disease is being considered.

Coding guidelines

Compatibility

Legacy and official ICD code match exactly.
Legacy codes
E03.9

Common synonyms

Hypothyroidism, unspecifiedHypothyroidism

Frequently asked questions

Code details

CodeE03.9
SystemICD10
Display nameHypothyroidism, unspecified
ChapterEndocrine, nutritional and metabolic diseases (E00-E89)
BlockDisorders of thyroid gland

Flags

BillableYes
Valid clinical useYes

Source

SourceICD-10
Version2026-annual
Releaseannual
Year2026

Index terms

Matched terms
Anemia(essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)Arthritis, arthritic(acute) (chronic) (nonpyogenic) (subacute)ArthropathyAtaxia, ataxy, ataxicAtrophy, atrophic(of)Cataract(cortical) (immature) (incipient)Degeneration, degenerativeDementia(degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety)Dementia(degenerative (primary)) (persisting) (unspecified severity) (without behavioral disturbance, psychotic disturbance, mood disturbance, and anxiety)Hoffmann's syndromeHypothyroidism(acquired)Insufficiency, insufficient
See also
subcategory M14.8-Dementia, in, diseases specified elsewhere

About this content

This page is prepared by HealthAssure's clinical team using official coding standards from ICD-10. AI tools assist with drafting explanations, which are then reviewed and verified by healthcare professionals for accuracy. This content is for informational purposes and does not replace professional medical advice. Meet our team.