Go back up to this post and read the links:
Pay attention to units and example for all the fT options.
Also this plot i did:
Even the “gold standard” equilibrium dialysis assays for fT havent been standardized across US reference laboratories yet. CDC is working on it. Examples above show that calculated fT by Veremulen method typically a decent estimate. Direct RIA free T method correlates with true fT but it is a factor typically 6-7 off once you keep track of units. Most people are not trained in units so are confused as hell and i dont blame them. It is very arcane. So numbers get thrown out without units and the shitshow continues.