What do the test results mean?

Thyroid function tests can tell the healthcare provider if there is a normal amount of thyroid hormone in the body. The general results of the test show if the overall thyroid hormone level is low, normal, or high.

Thyroid function tests can also help determine the cause of an abnormal thyroid level. For example, the test measures thyroid hormones and a pituitary hormone that stimulates the thyroid gland. If the thyroid hormone level is low, it may be due to a disease within the thyroid gland. It may also be due to a disease in the pituitary gland. This is because the thyroid gland will not secrete thyroid hormone unless the pituitary gland stimulates it. If a person is already taking thyroid hormone replacement pills, an abnormal level may mean that the dose needs to be adjusted.

The exact levels of the different components in thyroid function tests vary. The following can change what are considered normal values in the thyroid function tests:

The results of the thyroid function test should be discussed with the healthcare provider who ordered the test.