Thyroid UK
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Can anyone help me to understand my blood results?

Two weeks ago my GP agreed to raise my levothyroxine from 100mg to 125mg. My blood results two weeks later were as follows:

Serum free triiodothyronine level (XaERq) 4.81 pmol/L (3.6 - 6.5)

Serum free T4 level (XaERr) 18.6 pmol/L (9 - 19.1)

Serum TSH level (XaELV) Below range (0.07 miu/L (0.35 - 4.94)

What does this mean?

7 Replies

Two weeks is too soon. After changing doses you need to wait 6-8 weeks.

Your fT4 at the moment looks ok but fairly high so that will be why your TSH is below range. Your fT3 is ok.

Test again in 5 weeks' time and then you'll know if 125 is too much or not. What were your results on 100?



Sorry I do not know as this is the first time I have ever asked for a print out of my results. Receptionist always said they were within the normal range.

Will get them re-tested in 5 weeks as suggested.



More importantly how do you feel? My TSH is the same as your's and I feel good better than I have done for a long while.

Moggie x


Yes I am feeling a bit better, but I do not know if that has anything to do with my improved diet.

Thanks Moggie


The trouble with many people on here, myself included, sometimes feel so ill that we change several things all at once and then when we feel an improvement we dont know which change to attribute it

Moggie x


My TSH was also 0.07 last time and my endo was happy with this as FT3 and FT4 in normal range as yours are. Agree though that you need to have a blood test in 5 weeks time. x


Thanks Clarebear will do.


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