The TSH test is used to evaluate thyroid function and is usually ordered by the general practitioner or endocrinologist, to assess whether this gland is working properly, and in hypothyroidism, hyperthyroidism, or in the follow-up in case of differentiated thyroid cancer, as follicular or papillary, for example.
The thyrostimulant hormone (TSH) is produced by the pituitary gland and is intended to stimulate the thyroid to produce the hormones T3 and T4. When TSH values increase in the blood, this means that the concentration of T3 and T4 in the blood is lower. When in low concentrations, T3 and T4 are present in high concentrations in the blood. Find out what tests are essential for thyroid evaluation.
- Reference TSH values vary depending on the age of the person and the laboratory where the test is performed.
- And are generally:.
Symptoms associated with high TSH are typical of hypothyroidism, such as fatigue, weight gain, constipation, cold sensation, increased facial hair, difficulty concentrating, dry skin, weak, brittle hair and nails. Learn more about hypothyroidism.
Symptoms associated with low TSH are typical of hyperthyroidism, such as restlessness, palpitations, insomnia, weight loss, nervousness, tremors, and decreased muscle mass. In this case, it is normal for TSH to be low and T4 high, but if T4 is still between 01 and 04 µI / mL, this may indicate subclinical hyperthyroidism. Low TSH and low T4 can indicate anorexia nervosa, for example, but in all cases the diagnosis is made by the doctor who ordered the test. Learn more about treating hyperthyroidism.
The TSH test is based on a small blood sample, which must be taken with an empty head for at least 4 hours, and the collected blood is sent to the laboratory for analysis.
The best time to perform this test is in the morning, since the concentration of TSH in the blood varies throughout the day, before performing the test it is important to indicate the use of certain medications, especially thyroid remedies, such as levothyroxine , as they can interfere with the test result.
The ultrasensitive TSH test is a more advanced diagnostic method that can detect minimal amounts of TSH in the blood that the normal test could not identify. The diagnostic method used in laboratories is very sensitive and specific, and the ultra-sensitive TSH test is typically used in routine.
The TSH test may be prescribed in healthy people, only to evaluate thyroid function, and also in cases of hyperthyroidism, hypothyroidism, Hashimoto thyroiditis, thyroid hypertrophy, presence of benign or malignant thyroid nodule, during pregnancy, and also to control thyroid dose. replacement drugs, in case of removal of this gland.
This test is usually ordered for everyone over the age of 40, even if there is no thyroid disease in the family.