Why would T3 and T4 be in the normal range if TSH and FT4 are elevated?

[Jill500]

I have been taking synthroid for about 12 years with minor adjustments over the years.  I have had my TSH checked regularly and had adjustments in meds accordingly.  I find that when I am in the "normal" range for TSH I tend to get migraines nearly every day.  When my TSH drops below the normal range (on the .3-3.0 scale) I feel much better, i.e., more energy, happier, no headaches.  With a synthroid dosage of .150 my TSH was normal but I was experiencing chronic headaches, irregular periods and pre-menstrual type symptoms regularly.  My doctor adjusted my meds to have me take .200 twice a week and stay at .150 the rest of the week.  I feel MUCH better.  However, now my TSH is at .05 and my FT4 is at 2.43.  My T3 and T4 remain in the normal range though.  I'm not sure what to do as I feel so much better, yet my TSH is extremely low.

[goolarra]

Jill500:
I agree.  TSH correlates very badly with symptoms.  FT3 is the best indicator of thyroid status, followed by a distant FT4, and TSH almost doesn't even make it into the race.  The point of all this is to make you feel good, so hurray for you if your doctor is treating symptoms, not numbers.  He's a keeper!

skeeterknitwit:
I think the reason the lab asks if you're fasting is much more mundane than you might think.  The lab order forms include all categories of bloodwork.  Some are fasting-sensitive, others (like TSH) are not.  However, there's a little box at the top of the form that has to be checked as "fasting" or "non-fasting".  Silly as it sounds, I think they just ask because they have to check the box.  They probably would get a major slap on the wrist if they didn't ask.

[skeeterknitwit]

My Dr. says to go by symptoms, not numbers.  I think I'm one of the lucky ones.
I'm still going through the adjustment after RAI, so I'm pretty new to this thyroid thing.
My symptoms do not match my TSH at all.  My symptoms seem to change weeks to months after the change in TSH.
So, if your Dr. will treat your symptoms and allow you to continue your present RX, then do it!  If your Dr. wants to lower your meds, then BEG for the higher dose!

I've heard others talk about time of testing on TSH.  Seems if you test early in the morning and fasting, your TSH can be higher.  I've always been told that fasting is not required, but the lab always asks if I'm fasting.  Why ask if it really makes no difference?  Maybe it really does make a slight difference?