Thyroid UK
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Possible secondary hypothyroidism?

Could I have some opinions on my blood results please? Does the FT4 seem too low? I've had several thyroid nodules for years but always been told my function is normal, despite having many symptoms of underactive thyroid.

I had half of my thyroid removed 2 weeks ago due to a suspicious nodule and have just been diagnosed with follicular variant of papillary cancer. One of my treatment options is levothyroxine so obviously I want to make sure I understand my previous blood results before I go down that route.

(Bloods done prior to surgery)

TSH 0.5 (0.20 - 6.0 )

Free T4 12.6 (11.0 - 22.0 )

Free T3 5.4 (3.1 - 6.8 )

Thyroid Receptor Abs <0.40 (0.00 - 1.80)

Thanks :-)

7 Replies

Hi motherclanger,

I'm sorry you're having such a tough time.

I'm central hypothyroid and with your low TSH and low FT4 there certainly is a possibility that you could be central.

Most people think that central means that the TSH never rises. It can in fact rise to the top of the range and sometimes a little bit over BUT never beyond that.

Your FT3 is ok. I personally need mine about 6 to feel good if the top of the range is 6.8

It would be good for you to see that FT4 just above mid range which is what seems comfortable for most. However I seem to need mine in the upper 1/3 to feel good.


Thanks. I hope you don't mind me asking, how were you diagnosed with central hypothyroid and how is it treated? Does addressing the hypothyroidism treat it or do you have additional problems with pituitary?


I was diagnosed when both my FT4 and FT3 dropped below range but my TSH only rose to 6.

With these blood levels most people would have had a TSH in the 100's. I was at this stage very, very poorly. So much so that it is difficult to talk about because it was so frightening.

My other pituitary hormones were checked and we're all within range. I had no pituitary adenoma and had a STIM to check my adrenal response. All results were good.

They then decided that my condition was Tertiary ie in the hypothalamus. Secondary would be in the pituitary.

The umbrella terminology is Central because both conditions are treated with levothyroxine.


When testing my bloods the TSH is ignored ( because it doesn't work!) and they use the FT4 and FT3 to determine levels.

The aim is to keep the FT4 and FT3 in the upper 1/3 rd of the range. As I said earlier, my FT3 needs to be about 6 in a range 3.6-6.8

If it drops much lower, I have crippling depression.

My condition is isolated meaning that other hypothalamus hormones are not affected.

All Central hypothyroidism needs to be thoroughly investigated to rule out hypopituitarism which can affect adrenals, ovaries, growth hormones etc.

Isolated central hypothyroidism is rare and maybe gene based if no other physical reasons exist.

Hope that helps x


Forgot to say. I see an ENDO every 4 weeks because I am still not fully regulated. I can honestly say that I am very lucky to have such a great ENDO. My health has improved tenfold. I am working again and able to function relatively well. I do still get tired but I have come from a very poorly place and improvement is gradual but very possible!

This time next year I'll be running marathons......NOT! 😀


Thanks so much joesmum. That's all really helpful and I'm sorry you've been so ill x


You're really welcome. The positive thing to take away is that I am getting better.

If you are Central then hold on to that thought! 😊


Motherclanger, may I ask what your other treatment options were?

Those labs are euthyroid - I take it you weren't on any thyroid hormone replacement. However, what is more important is how your labs are in, say six weeks from now. Is the remaining half of your gland going to be able to cope? Why did they test the Thyroid Recptor abs? Why not TPOab and TgAB?


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