TSH, also known as thyrotropin, is a hormone secreted by the pituitary gland that controls and regulates the normal functioning of the thyroid gland and is an important test indicator for the treatment and diagnosis of normal functioning of the thyroid gland. The normal range for a normal person is between 0.24 and 4.2. If the indicator is high, it is called hypothyroidism, commonly known as hypothyroidism; if it is lower, it results in hyperthyroidism, commonly known as hyperthyroidism. TSH is often used as one of the common clinical indicators to diagnose whether a patient has hyper- or hypothyroidism, but thyrotropin indicators also fluctuate up and down with age. For example, in infants up to one year of age, normal values may range from 1.7-9.1; in children and adolescents, from 0.7-5.7; and in adults and middle-aged adults, the normal reference range is generally between 0.4-4.2. For people below or above these values, it is necessary to check thyroglobulin to indirectly determine how much thyroid hormone is present, especially for some people with symptoms of hypothyroidism after thyroid surgery, this value will be different and will often be higher, but will not have too many side effects on the body. The value of TSH varies subtly from age to age, and it also varies in patients with hyperthyroidism, and is often used by doctors on a daily basis.