The Thyroids stimulating hormone TSH test is used to evaluate the functions related to the thyroid gland. This test is not a routine one and is usually ordered only when a person is experiencing symptoms of hyperthyroidism or hypothyroidism. It can also be ordered along with other tests such as a T4 test or a T3 test, both of which are tests for the thyroid gland. Some of the other tests of thyroid include the thyroid antibody test.
Testing is usually done in order to diagnose a person who has been exhibiting the symptoms of thyroid disorder. Newborns are often given this test to check whether their thyroid gland is functioning optimally. If a person is undergoing thyroid replacement therapy, the test may be given to monitor the treatment. Some times, the test may also be used to monitor the functioning of the pituitary gland.
Females, who have problems of infertility, may also be given the test. The TSH can help diagnose infertility and monitor its treatment. A thyroid stimulating hormone blood test may also be recommended for those who have a enlarged thyroid gland and are suffering from a condition known as goiter.
In the US, the test has been recommended for all new born babies as well as adults who are older than 35 years of age. This can help in screening for thyroid and growth related disorders. The test is performed on a sample of blood. The interpretation of thyroid stimulating hormone test results depend on the purpose for which the test is performed. When the TSH value is high, it is usually an indication of unresponsiveness of the thyroid gland to the hormone. This may mean that the thyroid gland is underactive. It is rare for a tumor to cause high values of TSH.
When the TSH values are lower than the normal limit, it means that the thyroid gland is overactive and is using up more hormone than necessary. This could also be a result of treatment with an unregulated dosage of thyroid hormone medication. In a rare case, there is a possibility of the pituitary gland being damaged. Such damage can cause the gland to produce lower amounts of TSH.
The TSH test results could indicate whether there is an excess or deficiency of the hormone. However, it is not possible to ascertain the exact cause of such an excess or deficiency of the hormone, without additional investigative tests.