Thyroid UK

Could anyone please explain these results?


I'm newly diagnosed overactive and at the endo for first appointment on Thursday but would like to be armed with a bit of knowledge. I've had 3 recent blood tests these are the results.

November 2013

TSH- >0.5

FT4- 18.4

FT3- 5.2

24th December

TSH- >0.5

FT4- 20.2

FT3- 6.1

7th January

TSH- >0.5

FT4- 23.1

FT3- 5.8

I'm not on any medication yet. I would be very grateful if someone's could explain them. Thank you.

8 Replies

TSH is Thyroid Stimulating Hormone. Pituitary gland produces this to instruct thyroid gland to produce T4. Your TSH is working too hard and needs to be slowed down.

FT4 is Free T4 the 'storehouse' prohormone which converts in the liver to T3. Yours is being overstimulated.

FT3 is Free T3 the 'active' thyroid hormone which powers the cells in all the major organs including the brain. Also being overstimulated.

Imagine a car engine on high grade petrol with the pedal flat to the floor and the car chained to a stout post. That's you, over revving at the moment.

You are suffering from hyperthyroidism. Usual symptoms include racing heart, palpitations, weightloss despite increased appetite, diarrhoea, tremors, breathlessness and possibly eye problems.

Endo will probably test your blood to see if you have Graves' antibodies, an autoimmune disease. You'll likely be given carbimazole or carbimazole+levothyroxine if 'block and replace' is deemed more appropriate.

Hyperthyroidism and Graves can go into remission after a while on medication. Sometimes it lasts and sometimes it recurs.

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Thankyou so much for the above explanation Clutter.

By the time I'd been diagnosed with Grave's disease, my brain was beyond

taking in new information, & although I looked at many sites thru Google, I

didn't see any that explained the TSH, FT3 & FT4 as clearly as you have.

Another thing I couldn't glean from any of the sites, was if Grave's disease

means there's a deficiency, or an overload of iodine. Can anyone here

tell me?

I love this site, by the way. I think you lot know more about thyroid problems

than those we pay to tell US! So thanks to you all who contribute :) xx


Thank you :) I think I was too ill to research inbetween my diagnosis and surgery. I could barely remember my name, address and DoB at the time so wouldn't have taken anything in.

When I did start researching I probably had to read things half a dozen times or more to take anything in. So many bookmarks of the same articles :-D

As I'm recovering it's becoming easier to read, remember and assimilate. 'Brain fog' was the first to improve. Body's still getting there. If you're very tired don't bother trying to take anything in. Bookmark and return to it.

Sorry,I don't know anything about iodine other than I had to avoid it prior to RAI ablatement. I've assumed that thyroid meds address iodine deficiency but may be wrong.



Where I live in the West Midlands those results would be well in range. Our ranges are TSH 0.35-6, FT4 9-26 and FT3 2.8-7. What are the ranges where you are?

Do you have any symptoms of hyper as listed in Clutter's post, or are you simply feeling awful because you have all that FT4 in your blood and you're not converting it efficiently to FT3?

What does anyone else think?


Anstey, it's the combination of low TSH, high in range and climbing FT4 and FT3 that point to hyperactivity.

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Thanks both for replying. That's a great explanation for a newbie. I am suffering from all the symptoms except weight loss. I also have very painful muscles which I'm taking gabapentin for, numb fingers, fatigue, forgetfulness, lack of concentration and generaly feeling Ill. I'm struggling to get all this information to stay in my brain, I would normally take it in very easily but seem to have a brain made of fog at the mo. Thanks for all being patient.


Twitter was perfect for me when I was first researching thyroid illness. Even I could manage 140 characters. Everything else had to be read and reread half a dozen times. Just bookmark stuff and revisit articles often.

When I started to recover 'brain fog' was the first symptom to improve.


Oh Thank you, that's good news! I'm so glad I found this site, it's really helping me understand a lot more.


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