Which tests they run depends on what your doctor orders...the good ones order at least FT3, FT4 and TSH for their thyroid patients at all labs.
It's hard to say if you were close, but 406 is extremely high. With a TSH that high, I certainly would have been watching out for any signs of coma. But, that's all behind you now. You need to make meds adjustments in very tiny increments (unless you are having major hyper symptoms)...maybe adjust by 12.5-25 at a time, then retest after four to five weeks to see if you need a further adjustment. When you increase or decrease by 50 mcg, you're almost guaranteed to be swinging back and forth from hypo to hyper.
how high does it have to be to go into a coma or die was i anywhere close?
Do they do that too when the do you blood work or do they just check TSH?
I just read your comment on a thread further down and see that your TSH is no longer 406.5 and that you are on meds. Changing your dose from 75 to 125 is too big a jump at once. Your doctor should be testing free T3 and free T4 and basing meds changes on those, not just TSH. It sounds like you might need a new doctor. 75 to 125 and then back down again is ridiculous. Plese provide all thyroid lab results along with their reference ranges. Also provide meds history with dates.
It's very bad. You need to have free T3 and free T4 tested immediately and start on meds if your FT3 and FT4 levels support your TSH. You must feel awful. Don't hesitate to go to the ER if you feel it necessary.