Thyroid Stimulating Hormone (TSH)
- Sample Type
- Standard
- Fasting
- No
- Unit
- mIU/L
TSH is a glycoprotein hormone secreted by the anterior pituitary gland to regulate the production of T4 and T3. In a Thyroid Function Test, TSH is the most sensitive first-line screening tool for thyroid dysfunction due to the inverse logarithmic relationship between TSH and free thyroid hormones. Small changes in thyroid hormone levels cause large changes in TSH, making it the primary marker for diagnosing subclinical and overt hypothyroidism or hyperthyroidism.
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Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
TSH levels exhibit a circadian rhythm (higher at night) and can be affected by Biotin (Vitamin B7) supplements, which cause falsely low TSH results. Severe non-thyroidal illness (Euthyroid Sick Syndrome) can also suppress TSH levels temporarily.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Thyroid Stimulating Hormone (TSH):
Official Sources
- ATA Guidelines & Statementsthyroid.org
- Hypothyroidism - StatPearls - NCBI Bookshelfncbi.nlm.nih.gov
Research & Guidelines
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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