TSH (Thyroid stimulating hormone) Test

TSH test is a kind of laboratory test that measures the level of thyroid stimulating hormone (TSH) in the blood. TSH test provides information about thyroid gland problems.

TSH Production

TSH production is controlled by hypothalamus. Hypothalamus produces TRH (thyrotropin releasing hormone) and this hormone induces TSH secretion from pituitary gland. TSH stimulates the thyroid gland to produce the thyroid hormones; T3 and T4 finally.

How the TSH test is performed ?TSH

If your doctor requests you to have a TSH blood test you’ll need to give a tube of blood. The technician/nurse will collect a little amount of blood from your arm veins, you may feel a little pain for a few seconds.  TSH test for babies is as simple as yours, a few drops of blood collection from heel can be enough for your baby’s TSH test.

Preparation for TSH test

If you take medicines for thyroid hormones level adjustment, TSH test should be done after 1 month to monitor the effects of treatment. No additinal preparations are needed for TSH test, but some factors may affect your test results.

Factor that may affect TSH test result

Some medications, imaging tests or other conditions may affect your TSH test result. You may stop using your medicines according to your doctors advice.

  • Dopamine
  • Lithium
  • Potassium iodide
  • Levodopa
  • Heparin
  • Corticosteroids
  • Prednisone
  • Amiodarone
  • Stress
  • Long time illness
  • Imaging tests with radioactive materials or iodine

Purpose of TSH test,why the TSH test is done ?

1- Monitoring thyroid gland’s condition, whether it is working properly or not

2- Monitoring hypothyroid (underactive thyroid gland) treatment

3- Monitoring hyperthyroid (overactive thyroid gland) treatment

4- Screening newborns for hypothyroidism (congenital hypothyroidism)

5- Researching the cause of hypothyroid symptoms like

  • Hair loss
  • Weight gain
  • Tiredness
  • Cold intolerance
  • Constipation
  • Dry skin
  • Fatigue
  • Menstrual irregularities

6- Researching the cause of hyperthyroid symptoms like;

  • Increased appetite
  • Weight loss
  • Anxiety
  • Rapid heart rate
  • Diarrhea
  • Difficulty sleeping

TSH test normal values

  • Adults: 0,4-4,2 mcU/mL
  • Children: 0,7-6,5 mcU/mL
  • Newborns: 1-39 mcU/mL

High TSH result means;

  • Underactive thyroid gland ; hypothyroidism
  • Acute or chronic thyroid gland disfunction
  • Pituitary gland tumors
  • Thyroid medicine dose may be inadequate for an underactive thyroid (hypothyroidism) treatment
  • Thyroid medicine dose may be excessive for an overactive thyroid (hyperthyroidism) treatment

Low TSH result means;

  • Overactive thyroid gland; hyperthyroidism
  • Thyroid medicine dose may be excessive for underactive thyroid (hypothyroidism) treatment
  • Pituitary gland damage; pituitary gland can’t produce enough TSH because of a damage
  • Graves disease
  • Toxic nodular goiter
  • Iodine amount may be too much in the body
  • Patient may be in the first trimester of pregnancy



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