High free T4 : Hi, I have just a blood test and... - Thyroid UK

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High free T4


Hi, I have just a blood test and got the following results...

Thyroid function test

Serum TSH level 0.28 miu/L [0.2 - 4.0]

Serum free T4 level 30.6 pmol/L [10.0 - 20.0]

Above high reference limit

Can anyone shed any light on these..? I've Ben having trouble staying asleep. Feel OK in myself, been cycling alot and lost as about a stone in the last 5 months..

I go to bed and wake up 4 - 5 hours later... Feeling like I've not slept...


3 Replies

Your levels are too high. Are you taking any thyroid hormone? If not you may be developing an overactive Thyroid and you need medical advice. You’ve either lost weight so need less or have levels too high and so have lost weight. Maybe you’ve been cycling to use up the energy generated by high T4.

Not enough information, James. Do you have any sort of diagnosis? Are you taking any thyroid hormone?

Just testing the TSH and FT4 doesn't tell the full story. You also need to have an FT3 result, and - most importantly - antibody results.

If you don't already have a diagnosis, the average GP is going to look at these results and tell you you have Grave's. However, a more realistic diagnosis would be Hashimoto's Thyroiditis - aka Autoimmune Thyroiditis - but I doubt your GP is capable of making that diagnosis. Which is why you absolutely need your antibodies tested - TRAB or TSI for Grave's, and TPO for Hashi's.

If I were you, I would refuse all medication until the antibodies have been tested and you have the results in your hands. :)


You also need vitamin D, folate, ferritin and B12 tested

Insomnia linked to low vitamin D and low B vitamins

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or vitamins


Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should ideally be done as early as possible in morning and fasting.

Essential to know antibodies results before assuming it's Graves' disease.....it's often Hashimoto's

If antibodies are high this is Hashimoto's, (also known by medics here in UK more commonly as autoimmune thyroid disease).

About 90% of all hypothyroidism in Uk is due to Hashimoto's. Low vitamins are especially common with Hashimoto's. Food intolerances are very common too, especially gluten. So it's important to get TPO and TG thyroid antibodies tested at least once .

Link about thyroid blood tests


Link about antibodies and Hashimoto's



List of hypothyroid symptoms


Private testing for suspected Graves - TSI or TRab antibodies


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