Yes, Iodine supplementation effects your blood tests / thyroid markers.

T4 blood levels tell how much Iodine your body is storing for use in the body
T3 blood levels tell how much T4 is being converted for use in the body

https://en.wikipedia.org/wiki/Thyroid_hormones - > note the illustrations and how many molecules of Iodine (I) are in each hormone molecule

TSH (Thyroid stimulating hormone) is created when the body is -asking- for iodine ( https://en.wikipedia.org/wiki/Thyroid_hormones#Effect_of_iodine_deficiency_on_thyroid_hormone_synthesis )



Since iodine supplementation directly effects TSH, t4 and t3 levels (reverse t3 and t4 are also common thyroid tests), you may both see a high TSH and low TSH.


If I were you, I'd seek out an iodine-educated doctor when considering getting those tests done - because if it's a high TSH you're likely to get a prescription for thyroid hormone (yeah, they do sell their own version of iodine), and if you have a low TSH, they may consider you hyperthyroid and try to intervene with thyroid treatment to lower your thyroid hormone production.


What do you want to get out of the testing?
The longer you've been supplementing iodine, the more adapted your system will be to the supplementation.


Many doctors believe excess iodine is pissed out within hours ( https://www.quora.com/How-do-you-cleanse-the-iodine-inside-your-body-after-a-CT-scan ).

If you're testing for progress on a hypothyroid status you've been working to correct through iodine supplementation -
remember that parasite cleanses are reccommended first. Lingering infections also effect thyroid hormone (t3 and t4) levels.

Yes. If you're like most of the population, taking Iodine will cause your TSH level to rise and your MD will be quick to diagnose you as hypothyroid and put you on synthroid. that is the present flowchart for endocrinologists. so, anyone in the world can basically be diagnosed as being hypothyroid, by merely taking a little Iodine before the test. That exhibits how lacking the MD's knowledge is, on an ancient topic. Imagine trusting them with anything else.... eek

You might search for the half-life of Iodine supplements.

The results may be different for 1mg doses of supplements rather than US RDA level supplements.

Learn about the various thyroid tests. TSH is very commonly used by insurance doctors; however the work horse thyroid hormone is T3.

Even if your test comes back negative, you may like the effect of related supplements--iodine, selenium, zinc, glandular supplements, maybe ashwagandha, etc.