The dosage is performed on a blood sample, which should not be taken on an empty stomach.

Normal values ​​depend on each individual and can vary depending on a multitude of factors including age, gender and genetics.

Pregnancy also changes the TSH level (this should be between 0,4 and 2,5 mIU / L in the first trimester of pregnancy and then rise). As an indication, on average, the reference values ​​are between 0,4 and 4 mIU / L.

In case of abnormally high TSH value (> 4 mIU / L) with normal or lowered free T4 level, hypothyroidism will be diagnosed. The causes are various, among others:

• Hashimoto thyroiditis, an autoimmune disease most commonly involved
• pituitary tumor (rare)
• taking medications (amiodarone, lithium, tamoxifen, etc.)
• incorrect dosage of thyroid replacement drugs

If, on the contrary, the TSH is abnormally low (

• Graves-Basedow’s disease
• secondary hypothyroidism (the pituitary gland does not produce enough TSH)
• excess iodine (drugs, thyroid nodules, etc.)
• pregnancy

Treatment will depend on the cause and the level of TSH and will aim to restore normal thyroid function.