Is a blood test used to check for thyroid gland problems.
TSH causes the thyroid gland to make two hormones: triiodothyronine (T3) and thyroxine (T4). T3 and T4 help control your body’s metabolism.
Why It Is Done
- To determine if the thyroid gland is working properly. An underactive thyroid gland (hypothyroidism) can cause symptoms such as weight gain, tiredness, dry skin, constipation, a feeling of being too cold, or frequent menstrual periods. An overactive thyroid (hyperthyroidism) can cause symptoms such as weight loss, rapid heart rate, nervousness, diarrhea, a feeling of being too hot, or irregular menstrual periods.
- Find the cause of an underactive thyroid gland (hypothyroidism). TSH levels can help determine whether hypothyroidism is due to a damaged thyroid gland or some other cause (such as a problem with the pituitary gland or the hypothalamus).
- To keep track of treatment with thyroid replacement medicine for people who have hypothyroidism.
- To monitor the thyroid gland function in people who are being treated for hyperthyroidism. This treatment may include antithyroid medicine, surgery, or radiation therapy.
- Double-check the diagnosis of an underactive thyroid gland in a newborn (congenital hypothyroidism).
- Diagnose and monitor female infertility problems.