The level of some protein, which binds to some of the T4 and T3 and makes it temporarily inactive. The FT4 and FT3 tests measure only what isn't bound this way. This protein does not seem to be important otherwise.
The level of some protein, which binds to some of the T4 and T3 and makes it temporarily inactive. The FT4 and FT3 tests measure only what isn't bound this way. This protein does not seem to be important otherwise.