ICD-10 Code E03.9 – Hypothyroidism, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E03.9 – Hypothyroidism, unspecified
What it is
E03.9 identifies hypothyroidism when the record confirms underactive thyroid function but does not specify the cause, type, or severity. Use it when the documentation simply says hypothyroidism.
Clinical signs
Clinical features vary; refer to documentation. Commonly noted findings include fatigue, weight gain, cold intolerance, constipation, and slowed thinking, but these are not required for coding.
When to use this code
Use E03.9 when the provider documents hypothyroidism without further detail, such as primary, congenital, or postprocedural disease. It also fits when the chart does not identify an underlying cause. If the record later specifies a more exact type, code that diagnosis instead.
Do not use for
Do not use this code when the documentation names a specific form of hypothyroidism, such as congenital or postprocedural hypothyroidism. Check documentation if the condition is secondary to another disorder.
Coding tip
Query for specificity whenever the note says only “hypothyroidism,” because a more exact ICD-10 code may be available.