It does indicate a pituitary problem when first diagnosed, in other words if your TSH and total T4 were both low before meds, then your dr should have checked into a pituitary problem, but if not and its like that since being on meds, I don't think it does.
When I was originally diagnosed as HypoT three years ago Dr said I tested positive for thyroid antibodies, so guess that means Hashimoto's disease? My TSH back then was 12.5 with T4 around 5 so I was in a bit of a shoddy state!
I am guessing those T's are both Totals? Have you ever had your FREE levels tested?
A lot of times when on meds the TSH will go way down, but you really need to know where your FREE levels are since they are your actual thyroid hormones. The total tests are bound and active and the active is a very small amount of that, the active is what your body can actually use. If those are Free levels then yes, your T4 is quite low, even if its a total its quite low. Wish you had the T3 range as well, sometimes if the T3 is higher than the T4 its because the body doesn't have enough meds and is converting as much T4 to T3 as it can to keep you going.
TPO antibodies would indicate Hashimoto's, TSI indicates Graves, you probably have Hashi's.
Hi, Just thought I'd throw in my 2 cents worth here. Going by those labs results and the ranges it would appear that you're in Canada. I live in Ontario Canada and my Free T3 range is 2.6 - 5.7 pmol/L. I think those are standard Candian (metric) ranges.
I have a somewhat similar problem. Both my TSH and Free T4 are low too and yet my T3 is okay. I too wondered about a pituitary problem as my ovaries never developed as a teen and have primary amenorrhea.
Hope you get your T4 up. That's what I'm hoping to do. I'm finding it hard to get a doc who doesn't put so much worth in the TSH and gets nervous when it goes below range. They don't get it. They should be paying more attention to the Fre T4 values and not look so much at the TSH.
Does low TSH + low T4 mean Pituitary problem? 
