Thyroid Stimulating Hormone (TSH)
Thyroid function test
What This Test Measures
TSH is produced by the pituitary gland and tells your thyroid how much thyroid hormone to make. It's the most sensitive test for thyroid function.
Normal Reference Ranges
| Gender | Age Range | Normal Range | Unit |
|---|---|---|---|
| All | All ages | 0.4000 - 4.0000 | mIU/L |
Understanding Your Results
High
What it means: Elevated TSH typically indicates hypothyroidism (underactive thyroid). Your pituitary is working harder to stimulate an underperforming thyroid.
Common causes: Hashimoto's thyroiditis, iodine deficiency, thyroid surgery, certain medications.
Next steps: Your doctor may order additional tests (Free T4, thyroid antibodies) and may start thyroid hormone replacement therapy.
Low
What it means: Low TSH typically indicates hyperthyroidism (overactive thyroid). Your thyroid is producing too much hormone.
Common causes: Graves' disease, toxic nodular goiter, thyroiditis, excessive thyroid medication.
Next steps: Your doctor will order additional tests (Free T4, Free T3, thyroid antibodies, thyroid scan) and discuss treatment options.
Normal
What it means: Your TSH level is normal, indicating your thyroid is functioning properly.
Common causes: Healthy thyroid function and hormone balance.
Next steps: Continue regular monitoring, especially if you have thyroid symptoms or family history.
Medical Disclaimer
This information is for educational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Lab test results should always be interpreted by a qualified healthcare provider in the context of your complete medical history and current health status. Reference ranges may vary between laboratories. Always consult your doctor about your specific results.