Thyroid UK

Normal TSH &FT4 low FT3 what does it mean?

Hello! Thanks for letting me post here! I was wondering if someone could help me as Google has just confused me even more with the thousands of articles on thyroid issues. I have been feeling off for awhile now with aches in my wrist joints, racing heart beat, tiredness even if I sleep all day and night low energy and cannot lose weight. I have seen a doctor this week for a sever kidney/bladder infection and I mentioned all this and she said to test my thyroid. Yesterday I got a call from the nurse who said your TSH is normal and so is the FT4 but your FT3 is low so this is inconclusive and you should come back and test is 6 weeks. Huh? So is this something I should be worried about or? I have never had a thyroid problem before so I don't really know why to think? Can someone help? TSH 1.72 (0.35 - 4.94) FT4 11.91 (9.00-19.0) FT3 1.93 (2.60 -3.90)

Thanks Catherine x

3 Replies

Hi Catg, welcome to the forum.

'Normal' is a word we never use round here. It is meaningless because we are all individuals, and very different. What is 'normal' for one person, is not 'normal' for another. When the nurse said 'normal', what she meant was 'in range'. But that does not mean that it's 'normal' for you.

Your TSH is, shall we say, average, for someone not on thyroid hormone replacement. But, it's not a thyroid hormone, it's a pituitary hormone, and does not always represent thyroid status. Your TSH does not represent your thyroid status in this test, because your FT4 is low, and your FT3 is below range. TSH is supposed to rise when thyroid hormones are low, and decrease when they are high.

However, the TSH is not a reliable test because many things can affect it. It's only a rough guide. For example, the time of day the test is done. TSH is highest early in the morning, and decreases throughout the day. So, what time did you have this test done?

It also decreases when you eat. So, if you had your test done early in the morning, but had your breakfast first, then the TSH would still not be at its highest.

But, it could very well be that this test is a one-off, and that next time you do one, it could be completely different. So, that's why the say come back in six months to do another one. So, when you go back, make sure it's under the same circumstances, so that you can compare the two tests - same time of day, eaten or not eaten, etc.

However, the most important question - and the one that most doctors forget to ask! - is : how do you feel? Do you feel well, usually, apart from your kidney infection? Or do you have symptoms like fatigue, hair-loss, unexplained weight-gain, etc? So, my advice would be, go back for that second test, and then post the results here - reminding us of the first lot, when you do - and we'll be able to tell you more. In the meantime, read as much as you can - on here or elsewhere - so that you are forearmed if there is a problem. OK? :)


Your very low T3 will be the cause of so many of your symptoms. T3 is the active thyroid hormone and is needed in every cell of your body - cells of the brain - heart - skin - kidneys - gut - liver - and so on. So when the level is low there is not enough to go around and things begin to go wrong - sometimes without realising it.

The above link is the main website of this forum and there you will read everything you need to know about the thyroid. Check out the menu on the left of the Home Page and all the drop down menus covering so many things. So important to read and learn so we can manage this condition ourselves. It is the only route to wellness :-)

I am not a Medic - just a Hashimotos gal with a B12 issue and Crohns :-)


Thanks for the replies. It's all very confusing. So do you think that this is leading towards me having Hypothyroidism? I assume I will get all this from the doctor in 6 weeks but heck 6 weeks can be a looooong time when you waiting for something! Other than the kidney infection and the symptoms I mentioned medically I am well. The test was done at 13:00 and I had not eaten anything that day except water and not eaten much at all for the 3 days prior only small amounts of fruit as the kidney infection finished me off. thanks for the support! X


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