I've heard of people with hypothyroidism suffering from IBS-type symptoms so, diarrhea wouldn't be considered all-that-uncommon.
I wonder the same thing about those tests....perhaps it's an insurance thing? Or doctors going along with the standard (and less expensive) "thyroid profile" that some labs offer?
Since the "plain" T4 & T3 are often falsely elevated due to proteins in the blood, you don't really know why they were high - a hamburger, maybe?
The extensive and ongoing Nurses' Health Study has shown that healthy people have TSH around 1.0 (or even lower). There has been much discussion about the current TSH ranges to the extent that they might be too high.
That is why knowledgeable doctors will look at the thyroid hormone levels if TSH >2 and/or the patient presents with symptoms.
While there is no definitive test to confirm Hashi's - TPOab or anti-TPOab levels in the thousands can indicate Hashi's.....so can elevated TGab.
Glad I could help - it really takes the whole village to deal with thyroid disease 'cuz doctors just don't seem to make things easy.