How can you have high RT3 withouth high fT4?

[Guest guest]

If I understand it, it's the high T4 that turns into RT3. If that's

correct how can someone have high RT3 with a terrible ratio but not

have high T4?

My fT4 is 1.1 (range .8-1.8)

fT3 is 275 (range 230-420)

RT3 is 36 (range 11-32)

ratio .076

Am I missing something in my understanding how RT3 happens.