Hi Kathy,
It depends on how much their FT4 and FT3 levels have fallen. In someone who has started out with an FT4 of say 2.5 (0.8-1.8) who starts out on too high of an ATD dose and experiences a fall in FT4 to 0.5, you'll usually see a high rise in TSH. When the dose is adjusted properly, typically TSH falls back down to <.01, and the rise in TSH is obviously related to the ATD dose.
In the same person with the same dose change whose levels return to normal after the dose is adjusted, this can suggest a possible early remission. Say this person with the same labs initially and the same dose reduction after the FT4 fell now has a FT4 of 1.6 and a TSH of 0.3, this would tend more to suggest early remission. Whenever you start seeing a normal TSH with normal thyroid levels, remission is in the cards.
But as I mentioned before, this same person who seems headed for remission could encounter an environmental trigger or two and this could change their entire disease course. So while early remission can be probable or more likely, things can change. If only we had crystal balls, huh? Best, Elaine