Thyroxine and triiodothyronine can be measured as free thyroxine and free triiodothyronine , which are indicators of thyroxine and triiodothyronine activities in the body. They can also be measured as total thyroxine and total triiodothyronine , which also depend on the thyroxine and triiodothyronine that is bound to thyroxine-binding globulin . A related parameter is the free thyroxine index , which is total thyroxine multiplied by thyroid hormone uptake , which, in turn, is a measure of the unbound thyroxine-binding globulins.  Additionally, thyroid disorders can be detected prenatally using advanced imaging techniques and testing fetal hormone levels. 
The product is great but I ordered this assuming that it was in stock. The tracking number was updated immediately but a few days later tracking the package it only said that the label was created. I contacted customer support and they insisted that they shipped it and refused to cancel my order and give me a refund. They only said that I can return it for a refund. It stayed this way for over 2 weeks before it actually shipped. Since the company was dishonest about shipping the product and refused to cancel the order before it shipped I didn't trust them with returning the product for a refund so I kept it when it FINALLY arrived. They even blocked me from their face book page. I DON'T recommend this Icon Supplements.