A doctor may discover an enlarged thyroid gland simply by feeling the patient’s neck and having them swallow during a routine physical exam. In some cases, the doctor may also be able to feel the presence of nodules. The following tests may also help to diagnose a goiter:
A hormone test: Blood tests can determine the amount of hormones produced by the thyroid and pituitary glands. If the thyroid is underactive, the level of thyroid hormone will be low. At the same time, the level of thyroid-stimulating hormone (TSH) will be elevated because the pituitary gland tries to stimulate the thyroid gland to produce more thyroid hormone. Goiter associated with an overactive thyroid usually involves a high level of thyroid hormone in the blood and a lower than normal TSH level.
An antibody test: Some causes of goiter involve production of abnormal antibodies. A blood test may confirm the presence of these antibodies.
Ultrasonography: A wand-like device (transducer) is held over the neck. Sound waves bounce through the neck and back, forming images on a computer screen. The images reveal the size of the thyroid gland and whether the gland contains nodules that the doctor may not have been able to feel.