This means there is too much thryoid hormone being produced. If you have been off meds for 5-6 weeks and still have these levels there is likely over-production. An I-123 scan and uptake can help determine why the thyroid is over-active --- usually it's Graves or an over-active nodule. There would not likely be another organ causing this.
What exactly is an over-active nodule and what is an I-123 scan?
I-123 is a type of x-ray study that helps determine the cause of an over-active thyroid.
An over-active nodule is a lump in the thyroid that makes excessive thyroid hormone.
Does this kind of x-ray involve iodine?
yes the scan involves iodine, but not like the RAI done to ablate the thyroid.It sees how much of the the gland takes up the iodine,if the whole gland takes it up and it's over 35 percent(I think) then you might have Graves. It also shows nodules, which can spew out too much thyroid hormone too. You might have Hashi toxicosis where you can have both Hashi's and Graves at different times, it happens sometimes.