What does "Free Thyroxine" mean?

[sheenah]

I still haven't quite got my head around my blood test results (Sorry to be so thick!!)

It reads "Free thyroxine" (13.9 in a range of 12.0 - 22.0).

This looks low to me, but what are the implications?

The TSH was 5.07 (in a range of 0.27 - 4.2) Clearly high.

Taking the 2 together was does it mean?

Many Thanks XX

[HarryE]

Free thyroxine is FT4, so is the naturally produced thyroxine that is available for your body to convert into T3 which is what actually works in the cells. It should be in the top quarter of the range, so yours should probably be at about 19 to feel well.

The TSH is just how loudly the pituitary is shouting for the production of more thyroid hormone. So yours is shouting pretty loud. It should be about 1. Or they should other be wherever they are when you feel perfectly well

[sheenah in reply to HarryE]

XXX

[HarryE in reply to sheenah]

Does that make sense? I'm better at explanations if I can draw pictures

[susymac]

Free thyroxine is just the correct term for free T4, (triiodothyronine is T3). T4 (thyroxine) is the storage thyroid hormone, which converts to T3 which the body uses.

Yes, yours is very close to the bottom of the range, ideally youu want it in the top third, your TSH as you say is above the range, ideally you want that under 3, although the right level for each person varies quite a bit, some people are better when its near zero, I like mine over 1 1/2. As the tsh drops the T4 levels should rise and vice versa, its finding the balance that is right for you that matters

Are you on medication ? You should be, but some doctors do not start medicating until your TSH reaches 10, which is nothing short of disgraceful IMO

[HarryE in reply to susymac]

Yes, my TSH was 3.3 when first tested and I felt terrible!

[sheenah in reply to susymac]

Thanks for your answer - yes I have just started meds (NDT) Not from GP though I had to go privately or I thought I was going to keel over and die