Testing for Hyperthyroidism 

Knowing if you have an overactive thyroid may seem as simple as going through the checklist of symptoms, but the signs of overactive thyroid can mimic other conditions. 

A simple blood test will provide evidence of whether you have an overactive thyroid. The tests will look at thyroid-stimulating hormone levels, which will be low if the patient has hyperthyroidism. The tests will also look at levels of free thyroxine (Free T4), which will be higher in cases of hyperthyroidism. The blood tests may also look at triiodothyronine (T3) and thyroxine (T4) levels. But these tests may not be definitive.

For some, a specialist can perform a handful of tests to make a more accurate determination. This might include a scan of your thyroid using a radioactive substance so the doctor can get a picture of the thyroid. Your doctor can provide more information about the types of tests you might expect in order to determine whether you have an overactive thyroid.