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Thyroid UK
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Help Interpreting Results Please - Normal TSH, Low T4


I had my second child 10 months ago and my obstetric consultant said that my thyroid looked 'unusual' during pregnancy and to have it checked again following the birth.

I lost nearly all my pregnancy weight (about 2 stone) within 2 weeks of having my son and then around 6 months ago started to put it all back on. The weight gain has coincided with a combination of depression, antidepressants, tiredness, difficulty concentrating 'foggy brain' etc. so I arranged to have my tests redone as I thought I might be hypo.

Initially I just had my TSH done (Serum TSH level = 1.17 mIU/L) I was told that this result was normal, but I requested that my Free T4 and Free T3 be checked too.

I got the below results back today and my GP has said that my T3 is fine and the T4 is marginally below normal so he wants the tests repeated in 6 months time but said that there is no need for treatment at this time:

Serum TSH level = 1.08 mIU/L

Serum free triiodothyronine level = 4.5 pmol/L

Serum free T4 level = 11.2 pmol/L Abnormal ?Px. ?obese. ?euthyroid-sick. RSJ

I would say that both my T3 and T4 look on the low side?

Could anyone give me any advice, should I just go with the GP's recommendation or should I consider further investigation. Could I have a problem with my pituitary gland if my TSH is normal but my T4/T3 are low?

Any advice gratefully received. I really don't feel myself and really would like to get to the bottom of my symptoms.

Thanks :-)

PS: I have had a gastric bypass but all my other blood results including B12 have come back as normal.

7 Replies

Hi kmarch

I can't really give you any answers as I'm still way off finding out what my issues are years later but just wanted to say, it seems you are similar to me with your results etc.

After having my first and only child, I too lost the weight very quickly and in-fact got to skinny, then started to get really tired and slowly gained weight. I lived with the tiredness and weight gain for a long time as every time I went to the docs my results were normal( only TSH tested). It was only 3/4 years ago when I got really ill that I was diagnosed first with hypothyroid, then Fibromyalgia and CFS. My results were similar to yours, normal TSH and low/borderline FT4(FT3 not tested).

I've been on a low dose of T4 for years, which hasn't helped. FT4 and FT3 always low in bloods but TSH always normal. Had gazillions of tests(which apparently aren't accurate anyway). T3 helped for a while, along side T4 but then relapsed.

Endo is now looking into Pituitary and Hypothalmus with last lot of tests but no doubt they will be normal too. Have now decided to try T3 only and probably won't have endos support.

Don't know if my story helps in anyway but you're not alone, good luck with everything :)


No ranges supplied so we do not know exactly where your results fall in ranges. " Marginally below normal" tells us nothing except GP has not a clue if these FT4 results are actually below the range bottom. Please clarify with results plus each range.

Meantime head for search engine type in: Interpretation of Thyroid tests by Colin Dayan, choose Keck School of Medicine from results, only site I know of where you can read/print free of charge. Colin Dayan is professor so he knows what he is talking about.


Some people have a naturally low TSH, I do, however, you do need to rule out the Pituitary gland, the only reliable test, according to my Endo is 24 hour urine collection With a tiny dose of cortisone, prescribed at midnight and then a blood tests at exactly 9am. I would also rule out the Parathyroid too. PTH The first test is simple. blood test, must be AM, for PTH, corrected thyroid and vit D, if all high or 2 high and D high for you. Then a nuclear PTH scan and CT, large teaching hospital Also an ultra sound of the thyroid would be a good idea. Then the autoimmune ,, hormonal things,, vit D, B12+ foliates, needs to be high in range. Diabetes,and iron/ferritinn, needs to be well in range, The GP will do those, If nthing obvious or if there is, a referral to and Endo, but find a good one first, before asking for a referral. Listening is the most important quality.If you see a good Endo they would do all these tests if considered important, blood tests definitely are.You do not give ranges but if the usual FT3, then you may benefit from little more but only a few Endo`s would treat with it on this TSH ,as it lowers it.

Best wishes,



Hi again, meant to add as I do not recognise your name. If you wish to reply to a specific post, click on "Reply to this" under the post, so we know.



as you've had a gastric bypass you will have malnutrition, these need to be addressed

How long ago was your bypass? I had one too, mine was 5 years ago and I suffer with low b12, low vitamin D and low vitamin Bs, who knows even minerals and essential fatty acids.

there is plenty of research out there to prove that for most post gastric bypass patients the standard multivitamin/mineral replacement they give you after surgery will not be enough. For as many as 98% people they will need additional supplements.

You say your vitamin B12 is ok, really? what was the result? do you know? if not then please ask for the result with ranges, if your b12 is less than 500 then you are deficient (even if in range, UK range is too low and people below 500 are often still deficient). If you are not b12 deficient and you don't receive injections for b12 you will very much become deficient, it is only a matter of time mainly.

low vitamin D can make you feel rotten and help you to put on weight, have you had this tested lately?

essential fatty acids never get tested on NHS but on bypass you will become deficient for these, take one tablespoon of hemp oil daily (hemp oil has the correct ratio of omega 3/6/9).

I also take high mineral supplements, high vit D, b12 injections, B complex 50mg tablets.

your fT4 is below range, if your nutritional deficiencies are addressed then just because your TSH is in range it doesn't mean you don't have hypothyroidism..

My private doctor would put you on a trial of thyroid hormones with your results x


Thanks to all for your comments.

I spoke to my GP, asked him to read the Interpretation of Thyroid tests paper by Colin Dayan and expressed my concerns. He then spoke to a consultant biochemist who expressed the following view...

"TFT do not suggest hypothyroidism, T3 is reassuringly normal, if pituitary/hypothalamus axis affected then periods would be affected but has Mirena so may not have periods. Previously normal BP would not support Addisons disease.

He suggests to test pituitary axis FSH LH Prolactin and 17b oestradiol if normal then pituitary axis Ok."

Not really sure what that all means but at least my voice is being heard.


Hi there, my name is jeanette

Im suprised to be reading your posts & I have exactly the same low free T4 but normal everything else, despite having all the symptoms of low thyroid.

I wsee this is 9months ago that you posted, please can you tell me what happened? was it your pituinary gland?

Many thanks


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