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TSH (Thyroid-Stimulating Hormone) Test

⚠️ Update approaching🔬 Evidence: StrongEndocrine & Metabolism
Diğer adları: Thyroid stimulating hormone, Thyroid test, Thyrotropin
⚠️

Discuss your test results with your doctor. This page is for informational purposes only and does not provide a diagnosis.

⚡ Key Facts

• Measures thyroid-stimulating hormone released by the pituitary gland • One of the key tests for evaluating thyroid function • Normal range: approximately 0.4–4.0 mIU/L (varies by age and lab) • High TSH may suggest underactive thyroid; low TSH may suggest overactive thyroid

🧪 What Does This Test Measure?

The TSH test measures thyroid-stimulating hormone released by the pituitary gland, serving as the primary screening test for thyroid function.

📋 Why Is It Ordered?

Ordered for evaluation of thyroid dysfunction and treatment monitoring. May also be used for screening in certain clinical situations.

🔧 Preparation

Fasting is generally not required for TSH testing. Early morning collection may help produce more consistent results.

📊 Reference Ranges

Normal: approximately 0.4–4.0 mIU/L Low: <0.4 mIU/L — hyperthyroidism evaluation High: >4.0–4.5 mIU/L — hypothyroidism evaluation ⚠️ These values may vary by age, pregnancy status, and laboratory.

⬆️ High Values

High TSH generally suggests the thyroid is underactive. It may be associated with Hashimoto's thyroiditis, iodine deficiency, or post-thyroid surgery.

⬇️ Low Values

Low TSH generally suggests the thyroid is overactive. It may be associated with Graves' disease, thyroid nodules, or excessive thyroid medication.

⚙️ What Can Affect Results?

Age, medications, supplements (biotin), circadian rhythm, pregnancy, and concurrent illness are key factors that may affect TSH results.

🔬 Evidence Summary

Strong evidence: 2 guidelines, 1 meta-analysis, 1 review, 4 observational studies.

📚 Most Important Studies on This Topic

1

Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by AACE and ATA

Guideline· Endocrine Practice · 2012 · PMID: 23246686

2

Serum TSH, T(4), and Thyroid Antibodies in the United States Population (1988 to 1994): NHANES III

Observational· Journal of Clinical Endocrinology & Metabolism · 2002 · PMID: 11836274

3

Subclinical Hypothyroidism and the Risk of Coronary Heart Disease and Mortality

Meta-analysis· JAMA · 2010 · PMID: 20858880

✅ Key Takeaways

💡

What you learned: TSH is one of the key tests for evaluating thyroid function. If results are outside the normal range, they are typically evaluated alongside free T4 and additional tests as needed.

⛔

A single TSH result cannot diagnose thyroid disease on its own. Clinical findings and additional tests are needed for definitive evaluation.

🔬 Sources Used on This Page

9 sources · Most recent publication: 2023
📋
Guideline
Expert society and guideline recommendations
2
sources
📊
Systematic review / meta-analysis
Combined analysis of multiple studies
1
source
📖
Review
Comprehensive topic evaluation
2
sources
👁
Observational
Observational and cohort studies
4
sources
Overall assessment: Evidence level for this topic is strong. This page is supported by 2 guidelines, 1 systematic review/meta-analysis, 2 reviews, 4 observational studies.

📝 Questions to Ask Your Doctor

Be prepared for your appointment. Add questions to your list.

📋 References

[PMID: 37655789] Thyroid Stimulating Hormone and Thyroid Hormones (Triiodothyronine and Thyroxine): An American Thyroid Association-Commissioned Review of Current Clinical and Laboratory Status. Thyroid, 2023.
[PMID: 32118725] Assessment of Biotin Interference in Thyroid Function Tests. Medicine, 2020.
[PMID: 25266247] Guidelines for the Treatment of Hypothyroidism: Prepared by the ATA Task Force on Thyroid Hormone Replacement. Thyroid, 2014.
[PMID: 23246686] Clinical Practice Guidelines for Hypothyroidism in Adults: Cosponsored by AACE and ATA. Endocrine Practice, 2012.
[PMID: 21058882] An Approach for Development of Age-, Gender-, and Ethnicity-Specific Thyrotropin Reference Limits. Thyroid, 2011.
[PMID: 20858880] Subclinical Hypothyroidism and the Risk of Coronary Heart Disease and Mortality. JAMA, 2010.
[PMID: 19121255] Subclinical Hypothyroidism: An Update for Primary Care Physicians. Mayo Clinic Proceedings, 2009.
[PMID: 11836274] Serum TSH, T(4), and Thyroid Antibodies in the United States Population (1988 to 1994): NHANES III. Journal of Clinical Endocrinology & Metabolism, 2002.
[PMID: 10695693] The Colorado Thyroid Disease Prevalence Study. Archives of Internal Medicine, 2000.
Last reviewed: 3/26/2026
Next review: 3/26/2027

🔗 Related Topics

🩺 Hipotiroidizm🩺 Hipertiroidizm🩺 Hashimoto tiroiditi🧪 sT4 (serbest tiroksin)🧪 sT3 (serbest triiyodotironin)🧪 Anti-TPO (tiroid peroksidaz antikoru)
⚖️ This page does not replace medical advice. Make treatment decisions with your doctor.
Content is based on scientific studies indexed in PubMed and current clinical guidelines.