How is Graves’ disease diagnosed?

How is Graves’ disease diagnosed?

Your healthcare provider may make a diagnosis based on your symptoms, such as an enlarged thyroid, and family history of thyroid or autoimmune disease. You may also have these tests to confirm a Graves’ disease diagnosis:

  • Blood test: Thyroid blood tests measure TSI, an antibody that stimulates thyroid hormone production. Blood tests also check amounts of thyroid-stimulating hormones (TSH). A low TSH level indicates that the thyroid gland is producing too much hormone. The overproduction causes the pituitary gland to make less TSH.
  • Radioactive iodine uptake (RAIU) test: The thyroid collects iodine from blood to make thyroid hormone. With the RAIU test, you swallow a small amount of radioactive iodine. Ingesting a radioactive material might sound scary, but this treatment safely targets thyroid cells only — the rest of your body isn’t affected. A device measures the amount of iodine the thyroid gland absorbs. High levels of iodine absorption can be a sign of Graves’ disease.
  • Thyroid scan: A thyroid scan is an imaging test that utilizes radioactive material to look at how the thyroid is working. It is typically done by injecting a material called technetium before the test, waiting a short period of time and then creating images of the thyroid. During the scan, your provider will see a picture of the gland, as well as being able to see the gland’s uptake pattern. This pattern helps tell your provider how well the gland is working. It can also be a part of the diagnosis process in that if you have diffuse (spread out) high uptake, it’s likely Graves’ disease. If there are focal (specific) areas of uptake, this is more likely to be a different type of hyperthyroidism.

There are also two types of antibodies linked with Graves’ disease that may be detected during your tests. These antibodies include TSI (thyroid stimulating antibodies), as well as TBII (thyrotropin binding inhibitory immunoglobulins).

In some patients, there will be negative antibodies and the diagnosis will depend on their lab results (mainly TSH, but also FT4 and FT3), radioiodine uptake and thyroid scan.