Guide to ICD-10 Code E03.9 Hypothyroidism, Unspecified

E03.9 is the ICD-10 code assigned to unspecified hypothyroidism — a condition characterized by reduced production of thyroid hormones due to an unidentified or undocumented underlying cause in medical documentation.

This code is typically used when the provider confirms hypothyroidism but doesn’t specify whether it’s congenital, acquired, autoimmune (like Hashimoto’s), or drug-induced.

Patients treat with E03.9 may expression general indications of hypothyroidism such as:

• Fatigue
• Cold intolerance
• Weight gain
• Depression
• Constipation
• Dry skin
• Slow heart rate
• Memory issues
• Menstrual irregularities

Since the code is for unspecified hypothyroidism, further testing may be needed to identify the exact type and cause.

The ICD-10 system includes many specific hypothyroidism codes:

• E03.0 – Congenital hypothyroidism with drawn-out goiter
• E03.5 – Atrophy of thyroid (acquired)
• E03.2 – Hypothyroidism due to conducts or extra exogenous substances
• E03.9 – Hypothyroidism, unspecified

E03.9 is used when the medical record absences the aspect to al

The ICD-10 system includes many specific hypothyroidism codes:

• E03.0 – Congenital hypothyroidism with drawn-out goiter
• E03.5 – Atrophy of thyroid (acquired)
• E03.2 – Hypothyroidism due to conducts or extra exogenous substances
• E03.9 – Hypothyroidism, unspecified

E03.9 is used when the medical record absences the aspect to allocate a more specific code. It should ideally be used as a temporary or default diagnosis until more information is obtainedlocate a more specific code. It should ideally be used as a temporary or default diagnosis until more information is obtained

Yes, E03.9 is a legal and fully billable identification code under the ICD-10 classification system.
It can be used on claims for services like:

• Office visits
• Thyroid function tests
• Follow-up appointments
• Medication management

However, providers are encouraged to update documentation if more specific hypothyroidism information becomes available during follow-up.

Yes. For insurance coverage and claim approval, documentation should support:

• Symptoms consistent with hypothyroidism
• TSH or T4 test results
• A treatment plan (e.g., levothyroxine)

Payers often require evidence of testing or ongoing treatment to consider E03.9 as a medically necessary diagnosis.

Medical coders should assign E03.9 only when:

• The physician documents hypothyroidism but does not specify the cause.
• Extra medical facts are not available at the time of coding.
• The diagnosis was confirmed, but no type (e.g., autoimmune, drug-induced) was identified.

Important: If lab results, medication history, or notes point to a specific cause, coders should use a more detailed ICD-10 code instead.

When billing E03.9, common CPT codes may include:

• 84443 – TSH (Thyroid Stimulating Hormone) test
• 84436 – Total T4 test
• 99213 – Office/outpatient visit (established patient)
• 96372 – Therapeutic injection (e.g., thyroid hormone)

Always ensure documentation supports both the diagnosis and procedure performed.