ICD-10 Code E03.2 – Hypothyroidism due to medicaments and other exogenous substances (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E03.2 – Hypothyroidism due to medicaments and other exogenous substances
What it is
E03.2 identifies hypothyroidism caused by a medication, chemical, or other outside substance. Use it when documentation links the thyroid underactivity to an exogenous cause rather than to primary thyroid disease.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include fatigue, weight gain, cold intolerance, constipation, and slowed thinking, along with provider-noted hypothyroidism after exposure to a causative substance.
When to use this code
Use this code when the record states hypothyroidism is due to a drug, toxin, or other exogenous substance. It also fits cases where the provider documents medication-induced thyroid dysfunction and confirms hypothyroidism as the diagnosis.
Code the underlying cause only if it is separately documented and supported. If the note does not clearly connect the hypothyroidism to the substance, check documentation before assigning E03.2.
Do not use for
Do not use E03.2 for primary hypothyroidism, congenital hypothyroidism, or transient thyroid changes without documented causation. Check documentation if the record only mentions abnormal thyroid tests.
Coding tip
Make sure the provider explicitly links hypothyroidism to the medicament or exogenous substance before coding E03.2.