Reverse T3 and CT3M

[Anisa]

FT3 is far more useful than total T3. Knowing how much T3 exists in a form bound to protein is nearly completely useless information. It doesn't do anything other than tell you that there is T3 there. It is entirely inactive. I would never look at total T3.

I totally agree!

With one exception: the method of calculating the ratio between T3 and RT3. One can not calculate between different units of measurement. In order to calculate the ratio between two hormones, in principle, they should both be present in the same unit of measurement. Either "free" to "free" or "total" to "total". Because RT3 is available only as total measure, we need a total measure of both - RT3 and T3 - to calculate the proper ratio between these two. Ratio calculated between the free value of T3 and total value of RT3 can not be entirely correct.

Really interesting lecture about exactly the role RT3 plays in thyroid conditions Optimizing Thyroid Function - A Look at Reverse T3 -- The "Brake Pedal" of Our Metabolism.