Thyroid UK
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They did tt3 not ft3 .....if tt3 normal will ft3 also be normal?

After all the hardwork getting the lab to agree to take my t3.. I got the result today and its total t3 that I've had done. I asked for free t3,

My question is does it matter they did the wrong one? My result is 1.6 (0.9-2.5) so mid range.

This was a last chance to try and see what is wrong with me, my other results are on m profile. I am seeing the gp on Friday so not got much to fight for now, I could cry :-(

9 Replies

I had exactly the same done to me, just come back from the endo but forgot to ask why he did total. Mine was 1.3 (range 0.9-2.4). Don't know what it means either



From what I have seen and researched, some places do Free T3; other do Total T3.

Indeed, unusually, it doesn't seem only to be split by laboratory but by hospital as well! That is, at least one lab doe FT3 for one client hospital and TT3 for another!

Some people have argued that TT3 gives a smoother curve than FT3 which tends to be quite spikey.

The ratio of FT3 to TT3 is around 1:300 - so numerically FT3 is somewhere around three times the value of TT3 but is in units that are one thousandth the size!



Hi rod, I was with you until the last paragraph! Hehe,

If I was hypothyroid would the tt3 be normal then?

My free t4 is low end normal 11.6 (12-25).

Normal tsh at 1.9 (0.4-4.5)

So was hoping the free t3 would shed some light! I am so fed up, think dr skinner is going to be my next port of call as I have a referral. I cannot go on like this, I am weak and so so very tired.


Broadly speaking, TT3 and FT3 go along with each other in the same directions. But where TT3 is like a long, slow ocean swell, FT3 is like the Channel on a choppy day!

If FT3 were high, you'd expect TT3 to be high and vice versa.



In my book, your FT4 is low and your TT3 is not high enough. Your TSH does not reflect the low FT4 and middling TT3 and should be regarded as a suspect measure in your case.



Thank you, would you like to come along to the doctors on Friday and tell her this for me? ;-)


Sorry - already booked up to take someone to doctors on Friday afternoon too many miles away from you! :-)


Ah bugga.

My other half is coming with me to battle....she's a lovely doctor but I need t be tough with her now.



Hi My Lab did once by mistake, my Endo said that it was useless!!



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