Tests and Diagnosis:

Goiter may cause your neck to appear swollen. By examining your neck, your doctor can determine the degree of gland enlargement and the areas of tenderness. In some cases, your doctor may be able to feel the presence of nodules.

Diagnosing goiter may also involve:

• A hormone test. Blood tests can determine the amount of hormones produced by your thyroid and pituitary glands. If your 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 your pituitary gland tries to stimulate your 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 antibodies.

• Ultrasonography. A wand-like device (transducer) is held over your neck. Sound waves bounce through your neck and back, forming images on a computer screen. The images reveal the size of your thyroid gland and whether the gland contains nodules that your doctor may not have been able to feel.

• A thyroid scan. During a thyroid scan, you'll have a radioactive isotope injected into the vein on the inside of your elbow. You then lie on a table with your head stretched backward while a special camera produces an image of your thyroid on a computer screen. The time needed for the procedure may vary, depending on how long it takes the isotope to reach your thyroid gland. Thyroid scans generate information about the nature of the thyroid enlargement and the function of the gland.