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Normal TSH level in the blood

Blood test
Normal TSH level in the blood
Last update: 22/10/2020

What is the normal TSH (thyroid-stimulating hormone) level in the blood?

Men: 0.4 - 4 µUI/ml
Women: 0.4 - 4 µUI/ml
Children from 11 to 18 years old: < 4.3 µUI/ml
Children from 6 to 10 years old: < 4.8 µUI/ml
Children from 1 to 5 years old: < 6 µUI/ml
Newborns: < 15 µUI/ml

In the International System of Units (SI), TSH in the blood is measured in mU/L. The numeric values are the same in µUI/ml or in mU/L.

Why normal levels can differ across different labs?

Each laboratory must establish its own normal ranges for the total TSH (thyroid-stimulating hormone) in the blood. These ranges depend on the makeup of the local population, the technologies used and the accuracy of the measurement. There may be also slight differences in the normal levels, according to age, gender, race or ethnic origin, geographic region, diet, type of sample and other relevant status.

Your doctor will study the results along with your medical record, screenings, physical condition, symptoms and any other relevant information about your situation.

There are some circumstances that may alter the normal ranges:

  • Older people, above 80 years old, have a higher normal range. Values of 4.5 µUI/ml can be considered to be on the normal range.
  • TSH values differ along the day. The values are higher at night. That is why the TSH blood test should be done in the early morning.

What is the role of TSH (thyroid-stimulating hormone)?

TSH (thyroid-stimulating hormone), also called thyrotropin, is produced by the pituitary gland. TSH plays an important role in the regulation of thyroid hormones. If the level of thyroid hormones (T3 and T4) drops too low, the pituitary gland produces TSH to stimulate the thyroid gland to produce more hormones.

It works along with Thyrotropin-releasing hormone (TRH). The hypothalamus releases thyrotropin-releasing hormone (TRH), which stimulates the pituitary gland to release thyroid-stimulating hormone (TSH).

Thyroid hormones T3 (triiodothyronine) and T4 (thyroxine) plays an important role in the body because they have influence on metabolism, growth, development, heart rate, body temperature or blood pressure.

What is a total TSH (thyroid-stimulating hormone) blood test used for?

TSH (thyroid-stimulating hormone) blood test is used to detect thyroid disorders. This test is usually done along with T3 (triiodothyronine) and T4 (thyroxine) hormones. TSH is the test that gives more information about thyroid disorders because a value out of the normal range is usually a sign of a malfunction of the thyroid gland.

The TSH blood level is usually tested in a routine blood test.

High values of TSH in the blood may be a sign of primary hypothyroidism (T3 and T4 are below the normal range). Low values of TSH may be a sign of primary hyperthyroidism (T3 and T4 are above the normal range). Primary hypothyroidism or hyperthyroidism refers to a problem with the thyroid gland.

If the pituitary gland fails, TSH may be lower than normal. This situation is related to secondary hypothyroidism where T3 and T4 hormones will be also lower than normal. Secondary hypothyroidism is not a common disorder.

TSH values are also useful to control people taking thyroid medication. It is an optimal way to know if the dose of the given drugs are adequate for the treatment.

Where can I find more information about TSH (thyroid-stimulating hormone) level in the blood?

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Which values are considered a normal TSH (thyroid-stimulating hormone) level in the blood?

The following values are considered to be normal values:

IMPORTANT: These levels are expressed in µUI/ml. They are an example of a healthy man of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.

0.4 µUI/ml0.5 µUI/ml0.6 µUI/ml0.7 µUI/ml0.8 µUI/ml0.9 µUI/ml1 µUI/ml1.1 µUI/ml
1.2 µUI/ml1.3 µUI/ml1.4 µUI/ml1.5 µUI/ml1.6 µUI/ml1.7 µUI/ml1.8 µUI/ml1.9 µUI/ml
2 µUI/ml2.1 µUI/ml2.2 µUI/ml2.3 µUI/ml2.4 µUI/ml2.5 µUI/ml2.6 µUI/ml2.7 µUI/ml
2.8 µUI/ml2.9 µUI/ml3 µUI/ml3.1 µUI/ml3.2 µUI/ml3.3 µUI/ml3.4 µUI/ml3.5 µUI/ml
3.6 µUI/ml3.7 µUI/ml3.8 µUI/ml3.9 µUI/ml4 µUI/ml   
Medically reviewed by our Medical staff on 22/10/2020


  • Approved Guideline – Procedures for the Handling and Processing of Blood Specimens, H18-A3. 2004. Clinical and Laboratory Standards Institute.
  • HHS Publication, 6th ed., June 2020. Biosafety in Microbiological and Biomedical Laboratories. Available on:
  • Concise Book of Medical Laboratory Technology: Methods and Interpretations. 2nd Edition. 2015. Ramnik Sood. ISBN: 978-93-5152-333-8. Pag. 783.
  • Tietz. Fundamentals of Clinical Chemistry. Carl A. Burtis, Edward R. Ashwood, David E. Bruns, Barbara G. Sawyer. WB Saunders Company, 2008. Pag 766. ISBN: 978-0-7216-3865-2.
  • Laboratory tests and diagnostic procedures with nursing diagnoses (8th ed), Jane Vincent Corbett, Angela Denise Banks, ISBN: 978-0-13-237332-6, Pag. 400.

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