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Thyroid hormone in the blood.
Last reviewed: 05.07.2025
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Reference values (norm) of TSH concentration in blood serum: newborns - 1-39 mIU/l, adults - 0.4-4.2 mIU/l.
Thyroid-stimulating hormone is a glycoprotein secreted by the anterior pituitary gland. It acts primarily on the thyroid gland, stimulating the synthesis of T4 and T3 and their release into the blood.
Causes of increase and decrease of thyroid stimulating hormone
To determine the content of thyroid-stimulating hormone in the blood serum, RIA, ELISA and immunofluorescence analysis are used. The latter method is based on the use of monoclonal antibodies to thyroid-stimulating hormone and enhanced chemiluminescence, its sensitivity is two orders of magnitude higher than that of RIA and one order of magnitude higher than that of ELISA. Modern third-generation diagnostic kits allow detecting concentrations of thyroid-stimulating hormone less than 0.01 mIU/l, so they can be used to clearly differentiate between hyperthyroidism (reduced thyroid-stimulating hormone content) and euthyroidism (normal thyroid-stimulating hormone content). It is with determining the level of thyroid-stimulating hormone that diagnostics should begin if deviations in the hormonal activity of the thyroid gland are suspected.