1) The light in the darkness of Crooked EVIL doctors hiding behind the complexity of Thyroid Blood Tests to boost their income is this wonderful website: Use this site map to navigate. http://www.stopthethyroidmadness.com/site-map/
2) Calcium supplements can inhibit Iodine intake. You don't need calcium supplements if you are taking 5,000+ Vitamin D3. So too can Goitrogen Foods. Do a Google on Goitrogen Goods.
3) Lost in all of the complexity of T3, T4, TSH, RT3, etc etc is the simple fact that the thyroid hormone simply controls your body temperature. Body temp at 96 or 97 degrees? Then just slowly increase your "Natural Dessicated Hormone" until your body reaches 98.6 degrees. The crooked doctors will try to sell you on the synthetic crappola. See this: http://www.stopthethyroidmadness.com/temperature/
The main reason for the "Required Required Co-Supplements" is to support the NIS Symporter
It really sucks that we must learn all of this complicated stuff to protect ourselves from unscrupulous doctors who try to take advantage of our ignorance at every turn!
I have to agree with Trapper: All medical tests are designed to sell expensive drugs.