ICD-10 Code E02 – Subclinical iodine-deficiency hypothyroidism (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E02 – Subclinical iodine-deficiency hypothyroidism
What it is
E02 identifies subclinical hypothyroidism caused by iodine deficiency. You use it when thyroid function is mildly underactive, but the condition is specifically linked to lack of iodine.
Clinical signs
Clinical features may be minimal or absent, and findings often reflect early thyroid underactivity. Refer to documentation for any recorded goiter, fatigue, or laboratory evidence supporting the diagnosis.
When to use this code
Use E02 when the provider documents subclinical hypothyroidism and clearly attributes it to iodine deficiency. It is appropriate for outpatient or inpatient records when the diagnosis is established in the chart. If the cause is not stated, check documentation before assigning this code.
Do not use for
Do not use E02 for overt hypothyroidism, unspecified hypothyroidism, or thyroid disorders without documented iodine deficiency. If the record does not support a subclinical pattern, choose the more accurate code.
Coding tip
Code E02 only when both “subclinical hypothyroidism” and iodine deficiency are documented together.