Thyroid UK
84,022 members99,002 posts


Hi grateful if anyone could decipher/give me an idea of these blood tests results:

Serum free triododothyronine level: 3.8 pmol/L

Serum free T4 level: 21.8pmol/L

States: Thyroid function test NORMAL no action

Serum TSH level 0.5miu/L

Thyroid peroxidase antibod lev: POS

Comment says: results suggest adequate replacement.

I think the T4 is high because I was feeling so unwell I took too much to try and help the fatigue.


8 Replies

Hi Jan

It would be helpful if you could put the ranges of these results as labs differ throughout the UK and it makes it easier for members to comment.

Did you have your blood test as early as possible and not take any levo before it.?


Blood tests taken early morning no breakfast.

range: 3.9 - 6.8pmol/L for T3

Range 11-24pmol/L for T4

Range TSH 0.35-4.5 miu/L



Your FT4 doesn't look too high but I can't be sure without seeing the range. Your FT3 is low and will be the reason you have hypothyroid symptoms. What medication are you taking and how long have you been on your current dose?

Ask your GP to test ferritin, vitamin D, B12 and folate as hypothyroid patients are often deficient/low and these deficiencies can cause musculoskeletal pain, fatigue and low mood similar to hypothyroid symptoms. Post your results with the lab ref ranges and members will advise whether supplementation is required.


I take 100 micrograms of levothyroxine a day.

They only did thyroid.

My ferritin has been high for years but comments on blood tests always say: results suggest adequate replacement. I was wondering if a little T3 would do me good as I notice a lot of people say they feel better with some T4 and T3 combined? I know these results were out of step from my usual results - bit of a telling off from my doctor, but I was so fatigued I thought a bit more T4 would help.

Just need a bit of advice if maybe introducing T3 would be a good idea or if the T4 is working fine?


Jan, FT4 and TSH are good so you don't appear to be undermedicated on 100mcg but you aren't converting well as your FT3 is below range. I think a slightly reduced dose of Levothyroxine plus the addition of some T3 (Liothyronine) would be beneficial.

It would be a good idea to ask your GP to do the vitamin and mineral tests I recommended. If your ferritin continues to be high your GP should investigate the reason.

1 like

Thanks Clutter I'll have a word with her. I don't know why ferritin is always high have you any idea?


Jan, infection/inflammation, obesity, daily alcohol consumption can all cause high ferritin. I had markers for infection and inflammation which were probably responsible for my high ferritin in Nov but I haven't had it retested subsequently. Consistently high ferritin can indicate haemochromatosis or iron overload which is a genetic condition.


Could be infection/inflammation like you not felt well since being diagnosed with Reinke's Odema last month. Drink only a glass of red wine a day, don't smoke thinking it's genetic as you say. Ask them to test it. Thanks Clutter.


You may also like...